Dual catalyst system for producing LLDPE and MDPE copolymers with long chain branching for film applications

ABSTRACT

Disclosed herein are ethylene-based polymers generally characterized by a melt index of less than 15 g/10 min, a density from 0.91 to 0.945 g/cm3, a CY-a parameter at 190° C. from 0.2 to 0.6, an average number of long chain branches per 1,000,000 total carbon atoms of the polymer in a molecular weight range of 500,000 to 2,000,000 g/mol of less than 5, and a maximum ratio of ηE/3η at an extensional rate of 0.03 sec−1 in a range from 3 to 15. The ethylene polymers have substantially no long chain branching in the high molecular weight fraction of the polymer, but instead have significant long chain branching in the lower molecular weight fraction, such that polymer melt strength and bubble stability are maintained for the fabrication of blown films and other articles of manufacture. These ethylene polymers can be produced using a dual catalyst system containing a single atom bridged metallocene compound with an indenyl group and a cyclopentadienyl group, and an unbridged hafnium metallocene compound with two cyclopentadienyl groups.

BACKGROUND OF THE INVENTION

Polyolefins such as high density polyethylene (HDPE) homopolymer andcopolymer and linear low density polyethylene (LLDPE) copolymer can beproduced using various combinations of catalyst systems andpolymerization processes. Ziegler-Nana and chromium-based catalystsystems can, for example, produce ethylene polymers having goodextrusion processability, polymer melt strength in pipe and blow moldingapplications, and bubble stability in blown film applications, typicallydue to their broad molecular weight distribution (MWD).Metallocene-based catalyst systems can, for example, produce ethylenepolymers having excellent impact and toughness properties, but often atthe expense of poor extrusion processability, melt strength, and bubblestability.

In some end-uses, such as blown film, it can be beneficial to have theproperties of a metallocene-catalyzed ethylene copolymer, but withimproved processability, strain hardening, melt strength, and bubblestability. Accordingly, it is to these ends that the present inventionis generally directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

The present invention generally relates to ethylene polymers (e.g.,ethylene/α-olefin copolymers) characterized by a melt index of less thanor equal to about 15 g/10 min, a density in a range from about 0.91 toabout 0.945 g/cm³, a CY-a parameter at 190° C. in a range from about 0.2to about 0.6, an average number of long chain branches (LCBs) per1,000,000 total carbon atoms of the polymer in a molecular weight rangeof 500,000 to 2,000,000 g/mol of less than or equal to about 5(effectively, little to no long chain branching in the high molecularweight end), and a maximum ratio of η_(E)/3η at an extensional rate of0.03 sec⁻¹ in a range from about 3 to about 15 (the ratio of extensionalviscosity to 3 times the shear viscosity; for Newtonian fluids, theratio is 1, and strain hardening results in ratios greater than 1).Unexpectedly, there is substantially no long chain branching in the highmolecular weight fraction of these polymers that might adversely impactfilm properties, such as tear resistance. Beneficially, however, thereis a significant amount of long chain branching in the lower molecularweight fraction of the polymer, such that polymer melt strength andbubble stability are maintained. The ethylene polymers disclosed hereincan be used to produce various articles of manufacture, such as blownfilms and cast films.

Another aspect of this invention is directed to a dual catalyst system,and in this aspect, the dual catalyst system can comprise catalystcomponent I comprising a single atom bridged metallocene compound withan indenyl group and a cyclopentadienyl group, catalyst component IIcomprising an unbridged hafnium metallocene compound with twocyclopentadienyl groups, an activator, and optionally, a co-catalyst.

In yet another aspect, an olefin polymerization process is provided, andin this aspect, the process can comprising contacting any catalystcomposition disclosed herein with an olefin monomer and an optionalolefin comonomer in a polymerization reactor system under polymerizationconditions to produce an olefin polymer. For instance, the olefinmonomer can be ethylene, and the olefin comonomer can be 1-butene,1-hexene, 1-octene, or a mixture thereof.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects andembodiments may be directed to various feature combinations andsub-combinations described in the detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 presents a plot of the molecular weight distributions of thepolymers of Examples 1, 3, and 11-12.

FIG. 2 presents a plot of the molecular weight distributions of thepolymers of Examples 8-10.

FIG. 3 presents a plot of the short chain branch distribution across themolecular weight distribution of the polymer of Example 2.

FIG. 4 presents a plot of the short chain branch distribution across themolecular weight distribution of the polymer of Example 3.

FIG. 5 presents a plot of the short chain branch distribution across themolecular weight distribution of the polymer of Example 5.

FIG. 6 presents a plot of the ATREF profiles of the polymers of Examples8-11.

FIG. 7 presents an extensional viscosity plot (extensional viscosityversus shear rate) at 190° C. for the polymer of Example 10.

FIG. 8 presents a plot of the maximum ratio of η_(E)/3η at extensionalrates in the 0.03 to 10 sec⁻¹ range for the polymers of Examples 3 and8-10.

FIG. 9 presents a plot of the long chain branch distribution across themolecular weight distribution of the polymer of Example 3.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2nd Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Herein, features of the subject matter are described such that, withinparticular aspects, a combination of different features can beenvisioned. For each and every aspect and/or feature disclosed herein,all combinations that do not detrimentally affect the designs,compositions, processes, and/or methods described herein arecontemplated with or without explicit description of the particularcombination. Additionally, unless explicitly recited otherwise, anyaspect and/or feature disclosed herein can be combined to describeinventive features consistent with the present disclosure.

While compositions and methods are described herein in terms of“comprising” various components or steps, the compositions and methodsalso can “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise. For example, a catalyst compositionconsistent with aspects of the present invention can comprise;alternatively, can consist essentially of; or alternatively, can consistof; catalyst component I, catalyst component II, an activator, and aco-catalyst.

The terms “a,” “an,” “the,” etc., are intended to include pluralalternatives, e.g., at least one, unless otherwise specified. Forinstance, the disclosure of “an activator-support” or “a metallocenecompound” is meant to encompass one, or mixtures or combinations of morethan one, activator-support or metallocene compound, respectively,unless otherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

For any particular compound disclosed herein, the general structure orname presented is also intended to encompass all structural isomers,conformational isomers, and stereoisomers that can arise from aparticular set of substituents, unless indicated otherwise. Thus, ageneral reference to a compound includes all structural isomers unlessexplicitly indicated otherwise; e.g., a general reference to pentaneincludes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane, while ageneral reference to a butyl group includes an n-butyl group, asec-butyl group, an iso-butyl group, and a tert-butyl group.Additionally, the reference to a general structure or name encompassesall enantiomers, diastereomers, and other optical isomers whether inenantiomeric or racemic forms, as well as mixtures of stereoisomers, asthe context permits or requires. For any particular formula or name thatis presented, any general formula or name presented also encompasses allconformational isomers, regioisomers, and stereoisomers that can arisefrom a particular set of substituents.

The term “substituted” when used to describe a group, for example, whenreferring to a substituted analog of a particular group, is intended todescribe any non-hydrogen moiety that formally replaces a hydrogen inthat group, and is intended to be non-limiting. A group or groups canalso be referred to herein as “unsubstituted” or by equivalent termssuch as “non-substituted,” which refers to the original group in which anon-hydrogen moiety does not replace a hydrogen within that group.Unless otherwise specified, “substituted” is intended to be non-limitingand include inorganic substituents or organic substituents as understoodby one of ordinary skill in the art.

The term “hydrocarbon” whenever used in this specification and claimsrefers to a compound containing only carbon and hydrogen. Otheridentifiers can be utilized to indicate the presence of particulargroups in the hydrocarbon (e.g., halogenated hydrocarbon indicates thepresence of one or more halogen atoms replacing an equivalent number ofhydrogen atoms in the hydrocarbon). The term “hydrocarbyl group” is usedherein in accordance with the definition specified by IUPAC: a univalentgroup formed by removing a hydrogen atom from a hydrocarbon (that is, agroup containing only carbon and hydrogen). Non-limiting examples ofhydrocarbyl groups include alkyl, alkenyl, aryl, and aralkyl groups,amongst other groups.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and the like, as well as alloysand blends thereof. The term “polymer” also includes impact, block,graft, random, and alternating copolymers. A copolymer is derived froman olefin monomer and one olefin comonomer, while a terpolymer isderived from an olefin monomer and two olefin comonomers. Accordingly,“polymer” encompasses copolymers and terpolymers derived from any olefinmonomer and comonomer(s) disclosed herein. Similarly, the scope of theterm “polymerization” includes homopolymerization, copolymerization, andterpolymerization. Therefore, an ethylene polymer includes ethylenehomopolymers, ethylene copolymers (e.g., ethylene/α-olefin copolymers),ethylene terpolymers, and the like, as well as blends or mixturesthereof. Thus, an ethylene polymer encompasses polymers often referredto in the art as LLDPE (linear low density polyethylene) and HDPE (highdensity polyethylene). As an example, an olefin copolymer, such as anethylene copolymer, can be derived from ethylene and a comonomer, suchas 1-butene, 1-hexene, or 1-octene. If the monomer and comonomer wereethylene and 1-hexene, respectively, the resulting polymer can becategorized as an ethylene/1-hexene copolymer. The term “polymer” alsoincludes all possible geometrical configurations, unless statedotherwise, and such configurations can include isotactic, syndiotactic,and random symmetries. Moreover, unless stated otherwise, the term“polymer” also is meant to include all molecular weight polymers, and isinclusive of lower molecular weight polymers.

The term “co-catalyst” is used generally herein to refer to compoundssuch as aluminoxane compounds, organoboron or organoborate compounds,ionizing ionic compounds, organoaluminum compounds, organozinccompounds, organomagnesium compounds, organolithium compounds, and thelike, that can constitute one component of a catalyst composition, whenused, for example, in addition to an activator-support. The term“co-catalyst” is used regardless of the actual function of the compoundor any chemical mechanism by which the compound may operate.

The terms “chemically-treated solid oxide,” “treated solid oxidecompound,” and the like, are used herein to indicate a solid, inorganicoxide of relatively high porosity, which can exhibit Lewis acidic orBrønsted acidic behavior, and which has been treated with anelectron-withdrawing component, typically an anion, and which iscalcined. The electron-withdrawing component is typically anelectron-withdrawing anion source compound. Thus, the chemically-treatedsolid oxide can comprise a calcined contact product of at least onesolid oxide with at least one electron-withdrawing anion sourcecompound. Typically, the chemically-treated solid oxide comprises atleast one acidic solid oxide compound. The “activator-support” of thepresent invention can be a chemically-treated solid oxide. The terms“support” and “activator-support” are not used to imply these componentsare inert, and such components should not be construed as an inertcomponent of the catalyst composition. The term “activator,” as usedherein, refers generally to a substance that is capable of converting ametallocene component into a catalyst that can polymerize olefins, orconverting a contact product of a metallocene component and a componentthat provides an activatable ligand (e.g., an alkyl, a hydride) to themetallocene, when the metallocene compound does not already comprisesuch a ligand, into a catalyst that can polymerize olefins. This term isused regardless of the actual activating mechanism. Illustrativeactivators include activator-supports, aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, and the like.Aluminoxanes, organoboron or organoborate compounds, and ionizing ioniccompounds generally are referred to as activators if used in a catalystcomposition in which an activator-support is not present. If thecatalyst composition contains an activator-support, then thealuminoxane, organoboron or organoborate, and ionizing ionic materialsare typically referred to as co-catalysts.

The term “metallocene” as used herein describes compounds comprising atleast one η³ to η⁵-cycloalkadienyl-type moiety, wherein η³ toη⁵-cycloalkadienyl moieties include cyclopentadienyl ligands, indenylligands, fluorenyl ligands, and the like, including partially saturatedor substituted derivatives or analogs of any of these. Possiblesubstituents on these ligands can include H, therefore this inventioncomprises ligands such as tetrahydroindenyl, tetrahydrofluorenyl,octahydrofluorenyl, partially saturated indenyl, partially saturatedfluorenyl, substituted partially saturated indenyl, substitutedpartially saturated fluorenyl, and the like. In some contexts, themetallocene is referred to simply as the “catalyst,” in much the sameway the term “co-catalyst” is used herein to refer to, for example, anorganoaluminum compound.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the initial components of thedisclosed or claimed catalyst composition/mixture/system, the nature ofthe active catalytic site, or the fate of the co-catalyst, catalystcomponent I, catalyst component II, or the activator (e.g.,activator-support), after combining these components. Therefore, theterms “catalyst composition,” “catalyst mixture,” “catalyst system,” andthe like, encompass the initial starting components of the composition,as well as whatever product(s) may result from contacting these initialstarting components, and this is inclusive of both heterogeneous andhomogenous catalyst systems or compositions. The terms “catalystcomposition,” “catalyst mixture,” “catalyst system,” and the like, canbe used interchangeably throughout this disclosure.

The term “contact product” is used herein to describe compositionswherein the components are contacted together in any order, in anymanner, and for any length of time, unless otherwise specified. Forexample, the components can be contacted by blending or mixing. Further,contacting of any component can occur in the presence or absence of anyother component of the compositions described herein. Combiningadditional materials or components can be done by any suitable method.Further, the term “contact product” includes mixtures, blends,solutions, slurries, reaction products, and the like, or combinationsthereof. Although “contact product” can include reaction products, it isnot required for the respective components to react with one another.Similarly, the term “contacting” is used herein to refer to materialswhich can be blended, mixed, slurried, dissolved, reacted, treated, orotherwise combined in some other manner.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices, and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention.

Several types of ranges are disclosed in the present invention. When arange of any type is disclosed or claimed, the intent is to disclose orclaim individually each possible number that such a range couldreasonably encompass, including end points of the range as well as anysub-ranges and combinations of sub-ranges encompassed therein. Forexample, when a chemical moiety having a certain number of carbon atomsis disclosed or claimed, the intent is to disclose or claim individuallyevery possible number that such a range could encompass, consistent withthe disclosure herein. For example, the disclosure that a moiety is a C₁to C₁₈ hydrocarbyl group, or in alternative language, a hydrocarbylgroup having from 1 to 18 carbon atoms, as used herein, refers to amoiety that can have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, or 18 carbon atoms, as well as any range between these twonumbers (for example, a C₁ to C₈ hydrocarbyl group), and also includingany combination of ranges between these two numbers (for example, a C₂to C₄ and a C₁₂ to C₁₆ hydrocarbyl group).

Similarly, another representative example follows for the ratio of Mw/Mnof an ethylene polymer consistent with aspects of this invention. By adisclosure that the ratio of Mw/Mn can be in a range from about 3 toabout 10, the intent is to recite that the ratio of Mw/Mn can be anyratio in the range and, for example, can be equal to about 3, about 4,about 5, about 6, about 7, about 8, about 9, or about 10. Additionally,the ratio of Mw/Mn can be within any range from about 3 to about 10 (forexample, from about 3.5 to about 6), and this also includes anycombination of ranges between about 3 and about 10 (for example, theMw/Mn ratio can be in a range from about 3 to about 5, or from about 6to about 8). Further, in all instances, where “about” a particular valueis disclosed, then that value itself is disclosed. Thus, the disclosurethat the ratio of Mw/Mn can be from about 3 to about 10 also discloses aratio of Mw/Mn from 3 to 10 (for example, from 3.5 to 6), and this alsoincludes any combination of ranges between 3 and 10 (for example, theMw/Mn ratio can be in a range from 3 to 5, or from 6 to 8). Likewise,all other ranges disclosed herein should be interpreted in a mannersimilar to these examples.

The term “about” means that amounts, sizes, formulations, parameters,and other quantities and characteristics are not and need not be exact,but can be approximate and/or larger or smaller, as desired, reflectingtolerances, conversion factors, rounding off, measurement errors, andthe like, and other factors known to those of skill in the art. Ingeneral, an amount, size, formulation, parameter or other quantity orcharacteristic is “about” or “approximate” whether or not expresslystated to be such. The term “about” also encompasses amounts that differdue to different equilibrium conditions for a composition resulting froma particular initial mixture. Whether or not modified by the term“about,” the claims include equivalents to the quantities. The term“about” can mean within 10% of the reported numerical value, preferablywithin 5% of the reported numerical value.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed generally to low and medium densityethylene-based polymers having excellent strength and toughnessproperties, but with improved tear strength without sacrificingprocessability, strain hardening, melt strength, and bubble stability.Articles produced from these ethylene-based polymers can include blownfilms and cast films.

Generally, metallocene-derived ethylene-based polymers with long chainbranches have those long chain branches concentrated in the highmolecular weight fraction of the polymer. However, these (high molecularweight) long chain branches can be detrimental to tear resistance, suchas seen in low MD Elmendorf tear strengths in blown films and castfilms. Advantageously, the ethylene polymers disclosed herein havesubstantially no long chain branching in the high molecular weightfraction of the polymer; instead, significant amounts of long chainbranching are present in the lower molecular weight fraction of thepolymer.

These ethylene polymers can be produced, for example, with a dualmetallocene catalyst system in a single reactor. It was found that usinga first metallocene catalyst that preferentially produces lowermolecular weight polyethylene with relatively high LCB content incombination with a second metallocene catalyst that preferentiallyproduces higher molecular weight polyethylene with low levels of LCBcontent can result in the unique combination of polymer propertiesdescribed herein.

Ethylene Polymers

Generally, the polymers disclosed herein are ethylene-based polymers, orethylene polymers, encompassing homopolymers of ethylene as well ascopolymers, terpolymers, etc., of ethylene and at least one olefincomonomer. Comonomers that can be copolymerized with ethylene often canhave from 3 to 20 carbon atoms in their molecular chain. For example,typical comonomers can include, but are not limited to, propylene,1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and the like, orcombinations thereof. In an aspect, the olefin comonomer can comprise aC₃-C₁₈ olefin; alternatively, the olefin comonomer can comprise a C₃-C₁₀olefin; alternatively, the olefin comonomer can comprise a C₄-C₁₀olefin; alternatively, the olefin comonomer can comprise a C₃-C₁₀α-olefin; alternatively, the olefin comonomer can comprise a C₄-C₁₀α-olefin; alternatively, the olefin comonomer can comprise 1-butene,1-hexene, 1-octene, or any combination thereof; or alternatively, thecomonomer can comprise 1-hexene. Typically, the amount of the comonomer,based on the total weight of monomer (ethylene) and comonomer, can be ina range from about 0.01 to about 20 wt. %, from about 0.1 to about 10wt. %, from about 0.5 to about 15 wt. %, from about 0.5 to about 8 wt.%, or from about 1 to about 15 wt. %.

In one aspect, the ethylene polymer of this invention can comprise anethylene/α-olefin copolymer, while in another aspect, the ethylenepolymer can comprise an ethylene homopolymer, and in yet another aspect,the ethylene polymer of this invention can comprise an ethylene/α-olefincopolymer and an ethylene homopolymer. For example, the ethylene polymercan comprise an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, an ethylene/1-octene copolymer, an ethylene homopolymer, orany combination thereof; alternatively, an ethylene/1-butene copolymer,an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, or anycombination thereof; or alternatively, an ethylene/1-hexene copolymer.

An illustrative and non-limiting example of an ethylene polymer (e.g.,comprising an ethylene copolymer) of the present invention can have amelt index of less than or equal to about 15 g/10 min, a density in arange from about 0.91 to about 0.945 g/cm³, a CY-a parameter at 190° C.in a range from about 0.2 to about 0.6, an average number of long chainbranches (LCBs) per 1,000,000 total carbon atoms of the polymer in amolecular weight range of 500,000 to 2,000,000 g/mol of less than orequal to about 5, and a maximum ratio of η_(E)/3η at an extensional rateof 0.03 sec⁻¹ in a range from about 3 to about 15. This ethylene polymeralso can have any of the polymer properties listed below and in anycombination, unless indicated otherwise.

The densities of ethylene-based polymers disclosed herein often aregreater than or equal to about 0.91 g/cm³, and less than or equal toabout 0.945 g/cm³. Yet, in particular aspects, the density can be in arange from about 0.91 to about 0.94 g/cm³, from about 0.92 to about0.945 g/cm³, from about 0.92 to about 0.94 g/cm³, from about 0.925 toabout 0.945 g/cm³, or from about 0.922 to about 0.942 g/cm³.

Ethylene polymers described herein often can have a melt index (MI) ofless than or equal to about 15 g/10 min, less than or equal to about 10g/10 min, or less than or equal to about 5 g/10 min. In further aspects,ethylene polymers described herein can have a melt index (MI) in a rangefrom about 0.1 to about 10 g/10 min, from about 0.2 to about 5 g/10 min,from about 0.4 to about 4 g/10 min, or from about 0.75 to about 2.75g/10 min.

While not being limited thereto, the ethylene polymer also can have ahigh load melt index (HLMI) in a range from 0 to about 300 g/10 min;alternatively, from about 5 to about 100 g/10 min; alternatively, fromabout 10 to about 85 g/10 min; or alternatively, from about 25 to about75 g/10 min.

The ratio of high load melt index (HLMI) to melt index (MI), referred toas the ratio of HLMI/MI, is not particularly limited, but typicallyranges from about 15 to about 90, from about 15 to about 80, from about20 to about 80, from about 20 to about 60, or from about 20 to about 40.In this HLMI/MI ratio, the melt index is not equal to zero.

Unexpectedly, the ethylene polymers described herein can have a maximumratio of η_(E)/3η at an extensional rate of 0.03 sec⁻¹ in a range fromabout 3 to about 15. For Newtonian fluids, the ratio of extensionalviscosity to 3 times the shear viscosity is equal to 1, while the strainhardening due to long chain branching can lead to ratios of greaterthan 1. In one aspect, the maximum ratio of η_(E)/3η at the extensionalrate of 0.03 sec⁻¹ can range from about 3 to about 10, or from about 4to about 10, while in another aspect, the maximum ratio can range fromabout 4 to about 15, or from about 4 to about 12, and in yet anotheraspect, the maximum ratio can range from about 5 to about 11, or fromabout 5 to about 9. These ratios of extensional viscosity to three timesthe shear viscosity are determined using a Sentmanat ExtensionalRheometer (SER) at 150° C.

Additionally, while not being limited thereto, the ethylene polymer canbe characterized further by a maximum ratio of η_(E)/3η at anextensional rate of 0.1 sec⁻¹ in a range from about 2 to about 10;alternatively, from about 2 to about 8; alternatively, from about 2 toabout 6; alternatively, from about 3 to about 9; or alternatively, fromabout 3 to about 7.

In an aspect, ethylene polymers described herein can have a ratio ofMw/Mn, or the polydispersity index, in a range from about 3 to about 10,from about 3.5 to about 10, from about 3.5 to about 8, from about 3 toabout 6, or from about 3.5 to about 6. Additionally or alternatively,the ethylene polymer can have a ratio of Mz/Mw in a range from about 2to about 5, from about 2 to about 4.5, from about 2.2 to about 5, orfrom about 2.2 to about 4.

In an aspect, ethylene polymers described herein can have aweight-average molecular weight (Mw) in a range from about 50,000 toabout 250,000 g/mol, from about 60,000 to about 200,000 g/mol, fromabout 70,000 to about 185,000 g/mol, from about 65,000 to about 175,000g/mol, or from about 80,000 to about 140,000 g/mol. Additionally oralternatively, the ethylene polymer can have a number-average molecularweight (Mn) in a range from about 10,000 to about 50,000 g/mol, fromabout 10,000 to about 40,000 g/mol, from about 10,000 to about 38,000g/mol, or from about 12,000 to about 30,000 g/mol. Additionally oralternatively, the ethylene polymer can have a z-average molecularweight (Mz) in a range from about 150,000 to about 600,000 g/mol, fromabout 200,000 to about 550,000 g/mol, from about 200,000 to about500,000 g/mol, or from about 220,000 to about 450,000 g/mol.

In accordance with certain aspects of this invention, the IB parameterfrom a molecular weight distribution curve (plot of dW/d(Log M) vs. LogM; normalized to an area equal to 1) can be an important characteristicof the ethylene polymers described herein. The IB parameter is oftenreferred to as the integral breadth, and is defined as 1/[dW/d(LogM)]_(MAX). Generally, the IB parameter of the ethylene polymersconsistent with this invention can be in a range from about 1 to about2, from about 1 to about 1.8, or from about 1 to about 1.7. In oneaspect, the ethylene polymer can be characterized by an IB parameter ina range from about 1.1 to about 1.8, and in another aspect, from about1.1 to about 1.7, and in yet another aspect, from about 1.15 to about1.75.

While not limited thereto, ethylene polymers described herein can have azero-shear viscosity at 190° C. in a range from about 1000 to about1,000,000 Pa-sec, from about 1000 to about 50,000 Pa-sec, or from about2000 to about 10,000 Pa-sec. Moreover, these ethylene polymers can havea CY-a parameter from about 0.2 to about 0.6, such as from about 0.25 toabout 0.55, from about 0.3 to about 0.6, from about 0.3 to about 0.55,or from about 0.32 to about 0.52. Additionally or alternatively, theseethylene polymers can have a relatively short relaxation time, typicallyin a range from about 0.001 to about 0.15 sec, such as from about 0.002to about 0.1 sec, or from about 0.002 to about 0.025 sec. The zero-shearviscosity, the CY-a parameter, and the relaxation time are determinedfrom viscosity data measured at 190° C. and using the Carreau-Yasuda(CY) empirical model as described herein.

The average number of long chain branches (LCBs) per 1,000,000 totalcarbon atoms of the ethylene polymer in a molecular weight range of500,000 to 2,000,000 g/mol is less than or equal to about 5 (there iseffectively no LCB in the high molecular weight fraction of thepolymer). All average numbers of LCBs disclosed herein arenumber-average numbers. In some aspects, the average number of longchain branches (LCBs) per 1,000,000 total carbon atoms of the polymer inthe molecular weight range of 500,000 to 2,000,000 g/mol can be lessthan or equal to about 4, less than or equal to about 3, less than orequal to about 2, or less than or equal to about 1. In further aspects,the average number of LCBs in this molecular weight range can be belowthe detection limit.

In the overall polymer (using the Janzen-Colby model), the ethylenepolymers typically have levels of long chain branches (LCBs) in a rangefrom about 1 to about 10 LCBs, from about 1 to about 8 LCBs, from about1 to about 7 LCBs, or from about 1 to about 6 LCBs, per 1,000,000 totalcarbon atoms.

Moreover, the ethylene polymers typically have a conventional shortchain branching distribution (the SCB content decreases with molecularweight). This SCBD feature is quantified herein by the number of shortchain branches (SCBs) per 1000 total carbon atoms of the ethylenepolymer at the number-average molecular weight (Mn) that is greater (byany amount disclosed herein, e.g., at least 50% greater, or at least100% greater, or at least 200% greater, or at least 300% greater), thanat the weight-average molecular weight (Mw), and/or the number of SCBsper 1000 total carbon atoms of the ethylene polymer at Mn is greater (byany amount disclosed herein) than at the z-average molecular weight(Mz), and/or the number of SCBs per 1000 total carbon atoms of theethylene polymer at Mw that is greater (by any amount disclosed herein)than at Mz. These numbers of SCBs disclosed herein are number-averagenumbers.

In accordance with certain aspects of this invention, the ethylenepolymers described herein can have a unique analytic TREF (ATREF)profile. For instance, the ethylene polymer can have a peak ATREFtemperature (temperature of the highest peak on the ATREF curve in the40-110° C. range) of from about 83 to about 103° C., or from about 85 toabout 100° C. In some aspects, the peak ATREF temperature can be in arange from about 88 to about 98° C., or from about 90 to about 96° C.

Further, the ethylene polymer (e.g., the ethylene/α-olefin copolymer)can have an ATREF profile characterized by from about 0.5 to about 6 wt.% (or from about 1 to about 5 wt. %, or from about 1.5 to about 4.5 wt.%) of the polymer eluting below a temperature of 40° C.; by from about12 to about 26 wt. % (or from about 13 to about 24 wt. %, or from about14 to about 23 wt. %) of the polymer eluting between 40 and 76° C.; byfrom about 52 to about 82 wt. % (or from about 55 to about 80 wt. %, orfrom about 58 to about 75 wt. %) of the polymer eluting above atemperature of 86° C.; and the remainder of the polymer (to reach 100wt. %) eluting between 76 and 86° C.

In an aspect, the ethylene polymer described herein can be a reactorproduct (e.g., a single reactor product), for example, not apost-reactor blend of two polymers, for instance, having differentmolecular weight characteristics. As one of skill in the art wouldreadily recognize, physical blends of two different polymer resins canbe made, but this necessitates additional processing and complexity notrequired for a reactor product. Additionally, the ethylene polymer canfurther contain any suitable additive, non-limiting examples of whichinclude an antioxidant, an acid scavenger, an antiblock additive, a slipadditive, a colorant, a filler, a polymer processing aid, a UV additive,and the like, as well as any combination thereof.

Moreover, the ethylene polymers can be produced with a metallocenecatalyst system containing zirconium and hafnium, discussed furtherbelow. Ziegler-Natta, chromium, and titanium metallocene based catalystssystems are not required. Therefore, the ethylene polymer can contain nomeasurable amount of chromium or titanium (catalyst residue), i.e., lessthan 0.1 ppm by weight. In some aspects, the ethylene polymer cancontain, independently, less than 0.08 ppm, less than 0.05 ppm, or lessthan 0.03 ppm, of chromium and titanium.

Articles and Products

Articles of manufacture can be formed from, and/or can comprise, theolefin polymers (e.g., ethylene polymers) of this invention and,accordingly, are encompassed herein. For example, articles which cancomprise the polymers of this invention can include, but are not limitedto, an agricultural film, an automobile part, a bottle, a container forchemicals, a drum, a fiber or fabric, a food packaging film orcontainer, a food service article, a fuel tank, a geomembrane, ahousehold container, a liner, a molded product, a medical device ormaterial, an outdoor storage product, outdoor play equipment, a pipe, asheet or tape, a toy, or a traffic barrier, and the like. Variousprocesses can be employed to form these articles. Non-limiting examplesof these processes include injection molding, blow molding, rotationalmolding, film extrusion, sheet extrusion, profile extrusion,thermoforming, and the like. Additionally, additives and modifiers oftenare added to these polymers in order to provide beneficial polymerprocessing or end-use product attributes. Such processes and materialsare described in Modern Plastics Encyclopedia, Mid-November 1995 Issue,Vol. 72, No. 12; and Film Extrusion Manual—Process, Materials,Properties, TAPPI Press, 1992; the disclosures of which are incorporatedherein by reference in their entirety. In some aspects of thisinvention, an article of manufacture can comprise any of olefin polymers(or ethylene polymers) described herein, and the article of manufacturecan be or can comprise a blown film, a cast film, a pipe, or a blowmolded product.

In some aspects, the article produced from and/or comprising an ethylenepolymer of this invention is a film product. For instance, the film canbe a blown film or a cast film that is produced from and/or comprisesany of the ethylene polymers disclosed herein. Such films also cancontain one or more additives, non-limiting examples of which caninclude an antioxidant, an acid scavenger, an antiblock additive, a slipadditive, a colorant, a filler, a processing aid, a UV inhibitor, andthe like, as well as combinations thereof.

Also contemplated herein is a method for forming or preparing an articleof manufacture comprising any polymer disclosed herein. For instance, amethod can comprise (i) contacting a catalyst composition with an olefinmonomer (e.g., ethylene) and an optional olefin comonomer underpolymerization conditions in a polymerization reactor system to producean olefin polymer (e.g., an ethylene polymer), wherein the catalystcomposition can comprise catalyst component I, catalyst component II, anactivator (e.g., an activator-support comprising a solid oxide treatedwith an electron-withdrawing anion), and an optional co-catalyst (e.g.,an organoaluminum compound); and (ii) forming an article of manufacturecomprising the olefin polymer (or ethylene polymer). The forming stepcan comprise blending, melt processing, extruding, molding, orthermoforming, and the like, including combinations thereof. Anysuitable additive can be combined with the polymer in the meltprocessing step (extrusion step), such as antioxidants, acid scavengers,antiblock additives, slip additives, colorants, fillers, processingaids, UV inhibitors, and the like, as well as combinations thereof.

Films disclosed herein, whether cast or blown, can be any thickness thatis suitable for the particular end-use application, and often, theaverage film thickness can be in a range from about 0.25 to about 250mils, or from about 0.5 to about 20 mils. For certain film applications,typical average thicknesses can be in a range from about 0.25 to about 8mils, from about 0.5 to about 8 mils, from about 0.8 to about 5 mils, orfrom about 0.7 to about 2 mils.

In an aspect and unexpectedly, the blown films or cast films disclosedherein can have excellent tear resistance. Further, such films also cangenerally have low haze and good optical properties. For instance, thetear resistance of the films described herein can be characterized bythe MD (or TD) Elmendorf tear strength. Suitable ranges for the MD tearstrength can include, but are not limited to, from about 40 to about 400g/mil, from about 40 to about 250 g/mil, from about 40 to about 150g/mil, from about 45 to about 450 g/mil, from about 45 to about 200g/mil, from about 50 to about 350 g/mil, or from about 50 to about 150g/mil, and the like. Typical ranges for the TD tear strength caninclude, but are not limited to, from about 75 to about 600 g/mil, fromabout 100 to about 700 g/mil, from about 100 to about 550 g/mil, or fromabout 120 to about 550 g/mil, and the like.

While not being limited thereto, the blown film or cast film can have aratio of MD Elmendorf tear strength to TD Elmendorf tear strength(MD:TD) in a range from about 0.15:1 to about 0.7:1, such as from about0.15:1 to about 0.55:1, from about 0.2:1 to about 0.5:1, from about0.2:1 to about 0.45:1, or from about 0.25:1 to about 0.5:1.

The film products encompassed herein also can be characterized by verygood optical properties, such as low haze. As one of skill in the artwould readily recognize, certain additives can adversely impact haze andother optical properties, for example, slip and antiblock additives.Nonetheless, the film products encompassed herein can have a haze (withor without additives) of less than or equal to about 10%, or less thanor equal to about 9%, and often can have haze values ranging from about2 to about 10%, from about 3 to about 10%, from about 4 to about 9%, orfrom about 5 to about 10%, and the like.

Catalyst Systems and Polymerization Processes

In accordance with aspects of the present invention, the olefin polymer(e.g., the ethylene polymer) can be produced using a dual catalystsystem. In these aspects, catalyst component I can comprise any suitablesingle atom bridged metallocene compound with an indenyl group and acyclopentadienyl group, or any single atom bridged metallocene compoundwith an indenyl group and a cyclopentadienyl group disclosed herein.Catalyst component II can comprise any suitable unbridged hafniummetallocene compound with two cyclopentadienyl groups, or any unbridgedhafnium metallocene compound with two cyclopentadienyl groups disclosedherein. The catalyst system also can comprise any suitable activator orany activator disclosed herein, and optionally, any suitable co-catalystor any co-catalyst disclosed herein.

Referring first to catalyst component I, which can comprise a singleatom bridged metallocene compound with an indenyl group and acyclopentadienyl group. In some aspects, at least one of the indenylgroup and the cyclopentadienyl group can be substituted. Thus, theindenyl group can be substituted, the cyclopentadienyl group can besubstituted, or both the indenyl group and the cyclopentadienyl groupcan be substituted. For example, the metallocene compound can have anunsubstituted cyclopentadienyl group and an alkyl-substituted indenylgroup, such as a C₁ to C₆ alkyl group. The single atom bridge can be asingle carbon bridging atom or a single silicon bridging atom, which canhave two substituents independently selected from H or a C₁ to C₁₈hydrocarbyl group, or from H or a C₁ to C₆ alkyl group, and the like.The metal of the metallocene compound is not particularly limited, butgenerally, catalyst component I is a zirconium-based metallocene.

Catalyst component I can comprise, in particular aspects of thisinvention, a bridged metallocene compound having formula (A):

Within formula (A), M¹, R¹, R², R³, E¹, X¹, and X² are independentelements of the bridged metallocene compound. Accordingly, the bridgedmetallocene compound having formula (A) can be described using anycombination of M¹, R¹, R², R³, E¹, X¹, and X² disclosed herein.

In accordance with aspects of this invention, the metal in formula (A),M¹, can be Ti, Zr, or Hf. In one aspect, for instance, M¹ can be Zr orHf, while in another aspect, M¹ can be Ti; alternatively, M¹ can be Zr;or alternatively, M¹ can be Hf.

X¹ and X² in formula (A) independently can be a monoanionic ligand. Insome aspects, suitable monoanionic ligands can include, but are notlimited to, H (hydride), BH₄, a halide, a C₁ to C₃₆ hydrocarbyl group, aC₁ to C₃₆ hydrocarboxy group, a C₁ to C₃₆ hydrocarbylaminyl group, a C₁to C₃₆ hydrocarbylsilyl group, a C₁ to C₃₆ hydrocarbylaminylsilyl group,—OBR^(A) ₂, or —OSO₂R^(A), wherein R^(A) is a C₁ to C₃₆ hydrocarbylgroup. It is contemplated that X¹ and X² can be either the same or adifferent monoanionic ligand. In addition to representative selectionsfor X¹ and X² that are disclosed herein, additional suitable hydrocarbylgroups, hydrocarboxy groups, hydrocarbylaminyl groups, hydrocarbylsilylgroups, and hydrocarbylaminylsilyl groups are disclosed, for example, inU.S. Pat. No. 9,758,600, incorporated herein by reference in itsentirety.

In one aspect, X¹ and X² independently can be H, BH₄, a halide (e.g., F,Cl, Br, etc.), a C₁ to C₁₈ hydrocarbyl group, a C₁ to C₁₈ hydrocarboxygroup, a C₁ to Cis hydrocarbylaminyl group, a C₁ to C₁₈ hydrocarbylsilylgroup, or a C₁ to C₁₈ hydrocarbylaminylsilyl group. Alternatively, X¹and X² independently can be H, BH₄, a halide, OBR^(A) ₂, or OSO₂R^(A),wherein R^(A) is a C₁ to C₁₈ hydrocarbyl group. In another aspect, X¹and X² independently can be H, BH₄, a halide, a C₁ to C₁₂ hydrocarbylgroup, a C₁ to C₁₂ hydrocarboxy group, a C₁ to C₁₂ hydrocarbylaminylgroup, a C₁ to C₁₂ hydrocarbylsilyl group, a C₁ to C₁₂hydrocarbylaminylsilyl group, OBR^(A) ₂, or OSO₂R^(A), wherein R^(A) isa C₁ to C₁₂ hydrocarbyl group. In another aspect, X¹ and X²independently can be H, BH₄, a halide, a C₁ to C₁₀ hydrocarbyl group, aC₁ to C₁₀ hydrocarboxy group, a C₁ to C₁₀ hydrocarbylaminyl group, a C₁to C₁₀ hydrocarbylsilyl group, a C₁ to C₁₀ hydrocarbylaminylsilyl group,OBR^(A) ₂, or OSO₂R^(A), wherein R^(A) is a C₁ to C₁₀ hydrocarbyl group.In yet another aspect, X¹ and X² independently can be H, BH₄, a halide,a C₁ to C₈ hydrocarbyl group, a C₁ to C₈ hydrocarboxy group, a C₁ to C₈hydrocarbylaminyl group, a C₁ to C₈ hydrocarbylsilyl group, a C₁ to C₈hydrocarbylaminylsilyl group, OBR^(A) ₂, or OSO₂R^(A), wherein R^(A) isa C₁ to C₈ hydrocarbyl group. In still another aspect, X¹ and X²independently can be a halide or a C₁ to C₁₈ hydrocarbyl group. Forexample, X¹ and X² can be Cl.

In one aspect, X¹ and X² independently can be H, BH₄, a halide, or a C₁to C₃₆ hydrocarbyl group, hydrocarboxy group, hydrocarbylaminyl group,hydrocarbylsilyl group, or hydrocarbylaminylsilyl group, while inanother aspect, X¹ and X² independently can be H, BH₄, or a C₁ to C₁₈hydrocarboxy group, hydrocarbylaminyl group, hydrocarbylsilyl group, orhydrocarbylaminylsilyl group. In yet another aspect, X¹ and X²independently can be a halide; alternatively, a C₁ to C₁₈ hydrocarbylgroup; alternatively, a C₁ to C₁₈ hydrocarboxy group; alternatively, aC₁ to C₁₈ hydrocarbylaminyl group; alternatively, a C₁ to C₁₈hydrocarbylsilyl group; or alternatively, a C₁ to C₁₈hydrocarbylaminylsilyl group. In still another aspect, X¹ and X² can beH; alternatively, F; alternatively, Cl; alternatively, Br;alternatively, I; alternatively, BH₄; alternatively, a C₁ to C₁₈hydrocarbyl group; alternatively, a C₁ to C₁₈ hydrocarboxy group;alternatively, a C₁ to C₁₈ hydrocarbylaminyl group; alternatively, a C₁to C₁₈ hydrocarbylsilyl group; or alternatively, a C₁ to C₁₈hydrocarbylaminylsilyl group.

X¹ and X² independently can be, in some aspects, H, a halide, methyl,phenyl, benzyl, an alkoxy, an aryloxy, acetylacetonate, formate,acetate, stearate, oleate, benzoate, an alkylaminyl, a dialkylaminyl, atrihydrocarbylsilyl, or a hydrocarbylaminylsilyl; alternatively, H, ahalide, methyl, phenyl, or benzyl; alternatively, an alkoxy, an aryloxy,or acetylacetonate; alternatively, an alkylaminyl or a dialkylaminyl;alternatively, a trihydrocarbylsilyl or hydrocarbylaminylsilyl;alternatively, H or a halide; alternatively, methyl, phenyl, benzyl, analkoxy, an aryloxy, acetylacetonate, an alkylaminyl, or a dialkylaminyl;alternatively, H; alternatively, a halide; alternatively, methyl;alternatively, phenyl; alternatively, benzyl; alternatively, an alkoxy;alternatively, an aryloxy; alternatively, acetylacetonate;alternatively, an alkylaminyl; alternatively, a dialkylaminyl;alternatively, a trihydrocarbylsilyl; or alternatively, ahydrocarbylaminylsilyl. In these and other aspects, the alkoxy, aryloxy,alkylaminyl, dialkylaminyl, trihydrocarbylsilyl, andhydrocarbylaminylsilyl can be a C₁ to C₃₆, a C₁ to C₁₈, a C₁ to C₁₂, ora C₁ to C₈ alkoxy, aryloxy, alkylaminyl, dialkylaminyl,trihydrocarbylsilyl, and hydrocarbylaminylsilyl.

Moreover, X¹ and X² independently can be, in certain aspects, a halideor a C₁ to C₁₈ hydrocarbyl group; alternatively, a halide or a C₁ to C₈hydrocarbyl group; alternatively, F, Cl, Br, I, methyl, benzyl, orphenyl; alternatively, Cl, methyl, benzyl, or phenyl; alternatively, aC₁ to C₁₈ alkoxy, aryloxy, alkylaminyl, dialkylaminyl,trihydrocarbylsilyl, or hydrocarbylaminylsilyl group; alternatively, aC₁ to C₈ alkoxy, aryloxy, alkylaminyl, dialkylaminyl,trihydrocarbylsilyl, or hydrocarbylaminylsilyl group; or alternatively,methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,decyl, ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl,nonenyl, decenyl, phenyl, tolyl, benzyl, naphthyl, trimethylsilyl,triisopropylsilyl, triphenylsilyl, or allyldimethylsilyl.

In formula (A), E¹ can be C or Si, and R¹ and R² independently can be Hor a Ci to Cis hydrocarbyl group (e.g., a C₁ to C₈ hydrocarbyl group; aC₁ to C₁₂ alkyl group; or methyl, ethyl, propyl, butyl, pentyl, orhexyl). Alternatively, R¹ and R² can be connected to a form a cyclic orheterocyclic group having up to 18 carbon atoms or, alternatively, up to12 carbon atoms. Cyclic groups include cycloalkyl and cycloalkenylmoieties and such moieties can include, but are not limited to,cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, and the like. Forinstance, bridging atom E¹, R¹, and R² can form a cyclopentyl orcyclohexyl moiety. Heteroatom-substituted cyclic groups can be formedwith nitrogen, oxygen, or sulfur heteroatoms. While these heterocyclicgroups can have up to 12 or 18 carbons atoms, the heterocyclic groupscan be 3-membered, 4-membered, 5-membered, 6-membered, or 7-memberedgroups in some aspects of this invention.

R³ in formula (A) can be H or a hydrocarbyl or hydrocarbylsilyl grouphaving up to 18 carbon atoms. In one aspect, R³ can be hydrocarbyl grouphaving up to 12 carbon atoms, while in another aspect, R³ can be ahydrocarbylsilyl group having up to 12 carbon atoms (e.g., R³ can betrimethylsilyl). In another aspect, R³ can be H, methyl, ethyl, propyl,butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, ethenyl, propenyl,butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, phenyl,tolyl, or benzyl. In yet another aspect, R³ can be an alkyl or aterminal alkenyl group having up to 8 carbon atoms, or alternatively, upto 6 carbon atoms. In still another aspect, R³ can be methyl, ethyl,propyl, butyl, pentyl, or hexyl.

Illustrative and non-limiting examples of bridged metallocene compoundshaving formula (A) and/or suitable for use as catalyst component I caninclude the following compounds (Me=methyl, Et=ethyl, Pr=propyl,Bu=butyl, Ph=phenyl):

and the like, as well as combinations thereof.

Catalyst component II can comprise, in particular aspects of thisinvention, an unbridged hafnium metallocene compound with twocyclopentadienyl groups. Independently, each cyclopentadienyl group canbe substituted or unsubstituted. Thus, in one aspect, one of the twocyclopentadienyl groups can be substituted, while in another aspect,both cyclopentadienyl groups can be substituted.

If present, each substituent on the cyclopentadienyl group independentlycan be H, a halide, a C₁ to C₃₆ hydrocarbyl group, a C₁ to C₃₆halogenated hydrocarbyl group, a C₁ to C₃₆ hydrocarboxy group, or a C₁to C₃₆ hydrocarbylsilyl group. Importantly, each substituent on thecyclopentadienyl group(s) can be either the same or a differentsubstituent group. Moreover, each substituent can be at any position onthe cyclopentadienyl ring structure that conforms with the rules ofchemical valence. In general, any substituent independently can be H orany halide, C₁ to C₃₆ hydrocarbyl group, C₁ to C₃₆ halogenatedhydrocarbyl group, C₁ to C₃₆ hydrocarboxy group, or Ci to C₃₆hydrocarbylsilyl group described herein. In addition to representativesubstituents that are disclosed herein, additional suitable hydrocarbylgroups, halogenated hydrocarbyl groups, hydrocarboxy groups, andhydrocarbylsilyl groups are disclosed, for example, in U.S. Pat. No.9,758,600, incorporated herein by reference in its entirety.

In one aspect, for example, each substituent independently can be a C₁to C₁₂ hydrocarbyl group or a C₁ to C₁₂ hydrocarbylsilyl group. Inanother aspect, each substituent independently can be a C₁ to C₈ alkylgroup or a C₃ to C₈ alkenyl group. In yet another aspect, eachsubstituent independently can be H, Cl, CF₃, a methyl group, an ethylgroup, a propyl group, a butyl group, a pentyl group, a hexyl group, aheptyl group, an octyl group, a nonyl group, a decyl group, an ethenylgroup, a propenyl group, a butenyl group, a pentenyl group, a hexenylgroup, a heptenyl group, an octenyl group, a nonenyl group, a decenylgroup, a phenyl group, a tolyl group, a benzyl group, a naphthyl group,a trimethylsilyl group, a triisopropylsilyl group, a triphenylsilylgroup, or an allyldimethylsilyl group. In still another aspect, thecyclopentadienyl groups are the same or different, and arealkyl-substituted cyclopentadienyl groups, e.g., with a C₁ to C₆ alkylsubstituent.

Non-limiting examples of unbridged metallocene compounds that aresuitable for use as catalyst component II include, but are not limitedto, the following:

and the like, or combinations thereof.

According to an aspect of this invention, the weight ratio of catalystcomponent I to catalyst component II in the catalyst composition can bein a range from about 25:1 to about 1:25, from about 10:1 to about 1:10,from about 8:1 to about 1:8, from about 5:1 to about 1:5, from about 3:1to about 1:3; from about 2:1 to about 1:2, from about 1.5:1 to about1:1.5, from about 1.25:1 to about 1:1.25, or from about 1.1:1 to about1:1.1. In another aspect, catalyst component I is the minor component ofthe catalyst composition, and in such aspects, the weight ratio ofcatalyst component I to catalyst component II in the catalystcomposition can be in a range from about 1:1 to about 1:25, from about1:1 to about 1:20, from about 1:2 to about 1:10, or from about 1:3 toabout 1:15.

Additionally, the dual catalyst system contains an activator. Forexample, the catalyst system can contain an activator-support, analuminoxane compound, an organoboron or organoborate compound, anionizing ionic compound, and the like, or any combination thereof. Thecatalyst system can contain one or more than one activator.

In one aspect, the catalyst system can comprise an aluminoxane compound,an organoboron or organoborate compound, an ionizing ionic compound, andthe like, or a combination thereof. Examples of such activators aredisclosed in, for instance, U.S. Pat. Nos. 3,242,099, 4,794,096,4,808,561, 5,576,259, 5,807,938, 5,919,983, and 8,114,946, thedisclosures of which are incorporated herein by reference in theirentirety. In another aspect, the catalyst system can comprise analuminoxane compound. In yet another aspect, the catalyst system cancomprise an organoboron or organoborate compound. In still anotheraspect, the catalyst system can comprise an ionizing ionic compound.

In other aspects, the catalyst system can comprise an activator-support,for example, an activator-support comprising a solid oxide treated withan electron-withdrawing anion. Examples of such materials are disclosedin, for instance, U.S. Pat. Nos. 7,294,599, 7,601,665, 7,884,163,8,309,485, 8,623,973, and 9,023,959, which are incorporated herein byreference in their entirety. For instance, the activator-support cancomprise fluorided alumina, chlorided alumina, bromided alumina,sulfated alumina, fluorided silica-alumina, chlorided silica-alumina,bromided silica-alumina, sulfated silica-alumina, fluoridedsilica-zirconia, chlorided silica-zirconia, bromided silica-zirconia,sulfated silica-zirconia, fluorided silica-titania, fluorided-chloridedsilica-coated alumina, fluorided silica-coated alumina, sulfatedsilica-coated alumina, or phosphated silica-coated alumina, and thelike, as well as any combination thereof. In some aspects, theactivator-support can comprise a fluorided solid oxide and/or a sulfatedsolid oxide.

Various processes can be used to form activator-supports useful in thepresent invention. Methods of contacting the solid oxide with theelectron-withdrawing component, suitable electron withdrawing componentsand addition amounts, impregnation with metals or metal ions (e.g.,zinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, and the like, or combinations thereof),and various calcining procedures and conditions are disclosed in, forexample, U.S. Pat. Nos. 6,107,230, 6,165,929, 6,294,494, 6,300,271,6,316,553, 6,355,594, 6,376,415, 6,388,017, 6,391,816, 6,395,666,6,524,987, 6,548,441, 6,548,442, 6,576,583, 6,613,712, 6,632,894,6,667,274, 6,750,302, 7,294,599, 7,601,665, 7,884,163, and 8,309,485,which are incorporated herein by reference in their entirety. Othersuitable processes and procedures for preparing activator-supports(e.g., fluorided solid oxides, sulfated solid oxides, etc.) are wellknown to those of skill in the art.

The present invention can employ catalyst compositions containingcatalyst component I, catalyst component II, an activator (one or morethan one), and optionally, a co-catalyst. When present, the co-catalystcan include, but is not limited to, metal alkyl, or organometal,co-catalysts, with the metal encompassing boron, aluminum, zinc, and thelike. Optionally, the catalyst systems provided herein can comprise aco-catalyst, or a combination of co-catalysts. For instance, alkylboron, alkyl aluminum, and alkyl zinc compounds often can be used asco-catalysts in such catalyst systems. Representative boron compoundscan include, but are not limited to, tri-n-butyl borane,tripropylborane, triethylborane, and the like, and this includecombinations of two or more of these materials. While not being limitedthereto, representative aluminum compounds (e.g., organoaluminumcompounds) can include trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride,diethylaluminum ethoxide, diethylaluminum chloride, and the like, aswell as any combination thereof. Exemplary zinc compounds (e.g.,organozinc compounds) that can be used as co-catalysts can include, butare not limited to, dimethylzinc, diethylzinc, dipropylzinc,dibutylzinc, dineopentylzinc, di(trimethylsilyl)zinc,di(triethylsilyl)zinc, di(triisoproplysilyl)zinc,di(triphenylsilyl)zinc, di(allyldimethylsilyl)zinc,di(trimethylsilylmethyl)zinc, and the like, or combinations thereof.Accordingly, in an aspect of this invention, the dual catalystcomposition can comprise catalyst component I, catalyst component II, anactivator-support, and an organoaluminum compound (and/or an organozinccompound).

In another aspect of the present invention, a catalyst composition isprovided which comprises catalyst component I, catalyst component II, anactivator-support, and an organoaluminum compound, wherein this catalystcomposition is substantially free of aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, and/or other similarmaterials; alternatively, substantially free of aluminoxanes;alternatively, substantially free or organoboron or organoboratecompounds; or alternatively, substantially free of ionizing ioniccompounds. In these aspects, the catalyst composition has catalystactivity, discussed herein, in the absence of these additionalmaterials. For example, a catalyst composition of the present inventioncan consist essentially of catalyst component I, catalyst component II,an activator-support, and an organoaluminum compound, wherein no othermaterials are present in the catalyst composition which wouldincrease/decrease the activity of the catalyst composition by more thanabout 10% from the catalyst activity of the catalyst composition in theabsence of said materials.

Catalyst compositions of the present invention generally have a catalystactivity greater than about 250 grams of ethylene polymer (homopolymerand/or copolymer, as the context requires) per gram of activator-supportper hour (abbreviated g/g/hr). In another aspect, the catalyst activitycan be greater than about 350, greater than about 450, or greater thanabout 550 g/g/hr. Yet, in another aspect, the catalyst activity can begreater than about 700 g/g/hr, greater than about 1000 g/g/hr, orgreater than about 2000 g/g/hr, and often as high as 3500-6000 g/g/hr.Illustrative and non-limiting ranges for the catalyst activity includefrom about 500 to about 5000, from about 750 to about 4000, or fromabout 1000 to about 3500 g/g/hr, and the like. These activities aremeasured under slurry polymerization conditions, with atriisobutylaluminum co-catalyst, using isobutane as the diluent, at apolymerization temperature of about 80° C. and a reactor pressure ofabout 350 psig. Moreover, in some aspects, the activator-support cancomprise sulfated alumina, fluorided silica-alumina, or fluoridedsilica-coated alumina, although not limited thereto.

This invention further encompasses methods of making these catalystcompositions, such as, for example, contacting the respective catalystcomponents in any order or sequence. In one aspect, for example, thecatalyst composition can be produced by a process comprising contacting,in any order, catalyst component I, catalyst component II, and theactivator, while in another aspect, the catalyst composition can beproduced by a process comprising contacting, in any order, catalystcomponent I, catalyst component II, the activator, and the co-catalyst.

Olefin polymers (e.g., ethylene polymers) can be produced from thedisclosed catalyst systems using any suitable olefin polymerizationprocess using various types of polymerization reactors, polymerizationreactor systems, and polymerization reaction conditions. One such olefinpolymerization process for polymerizing olefins in the presence of acatalyst composition of the present invention can comprise contactingthe catalyst composition with an olefin monomer and optionally an olefincomonomer (one or more) in a polymerization reactor system underpolymerization conditions to produce an olefin polymer, wherein thecatalyst composition can comprise, as disclosed herein, catalystcomponent I, catalyst component II, an activator, and an optionalco-catalyst. This invention also encompasses any olefin polymers (e.g.,ethylene polymers) produced by any of the polymerization processesdisclosed herein.

As used herein, a “polymerization reactor” includes any polymerizationreactor capable of polymerizing (inclusive of oligomerizing) olefinmonomers and comonomers (one or more than one comonomer) to producehomopolymers, copolymers, terpolymers, and the like. The various typesof polymerization reactors include those that can be referred to as abatch reactor, slurry reactor, gas-phase reactor, solution reactor, highpressure reactor, tubular reactor, autoclave reactor, and the like, orcombinations thereof; or alternatively, the polymerization reactorsystem can comprise a slurry reactor, a gas-phase reactor, a solutionreactor, or a combination thereof. The polymerization conditions for thevarious reactor types are well known to those of skill in the art. Gasphase reactors can comprise fluidized bed reactors or staged horizontalreactors. Slurry reactors can comprise vertical or horizontal loops.High pressure reactors can comprise autoclave or tubular reactors.Reactor types can include batch or continuous processes. Continuousprocesses can use intermittent or continuous product discharge.Polymerization reactor systems and processes also can include partial orfull direct recycle of unreacted monomer, unreacted comonomer, and/ordiluent.

A polymerization reactor system can comprise a single reactor ormultiple reactors (2 reactors, more than 2 reactors, etc.) of the sameor different type. For instance, the polymerization reactor system cancomprise a slurry reactor, a gas-phase reactor, a solution reactor, or acombination of two or more of these reactors. Production of polymers inmultiple reactors can include several stages in at least two separatepolymerization reactors interconnected by a transfer device making itpossible to transfer the polymers resulting from the firstpolymerization reactor into the second reactor. The desiredpolymerization conditions in one of the reactors can be different fromthe operating conditions of the other reactor(s). Alternatively,polymerization in multiple reactors can include the manual transfer ofpolymer from one reactor to subsequent reactors for continuedpolymerization. Multiple reactor systems can include any combinationincluding, but not limited to, multiple loop reactors, multiple gasphase reactors, a combination of loop and gas phase reactors, multiplehigh pressure reactors, or a combination of high pressure with loopand/or gas phase reactors. The multiple reactors can be operated inseries, in parallel, or both. Accordingly, the present inventionencompasses polymerization reactor systems comprising a single reactor,comprising two reactors, and comprising more than two reactors. Thepolymerization reactor system can comprise a slurry reactor, a gas-phasereactor, a solution reactor, in certain aspects of this invention, aswell as multi-reactor combinations thereof.

According to one aspect, the polymerization reactor system can compriseat least one loop slurry reactor comprising vertical or horizontalloops. Monomer, diluent, catalyst, and comonomer can be continuously fedto a loop reactor where polymerization occurs. Generally, continuousprocesses can comprise the continuous introduction of monomer/comonomer,a catalyst, and a diluent into a polymerization reactor and thecontinuous removal from this reactor of a suspension comprising polymerparticles and the diluent. Reactor effluent can be flashed to remove thesolid polymer from the liquids that comprise the diluent, monomer and/orcomonomer. Various technologies can be used for this separation stepincluding, but not limited to, flashing that can include any combinationof heat addition and pressure reduction, separation by cyclonic actionin either a cyclone or hydrocyclone, or separation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess) is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, 6,833,415, and8,822,608, each of which is incorporated herein by reference in itsentirety.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used.

According to yet another aspect, the polymerization reactor system cancomprise at least one gas phase reactor (e.g., a fluidized bed reactor).Such reactor systems can employ a continuous recycle stream containingone or more monomers continuously cycled through a fluidized bed in thepresence of the catalyst under polymerization conditions. A recyclestream can be withdrawn from the fluidized bed and recycled back intothe reactor. Simultaneously, polymer product can be withdrawn from thereactor and new or fresh monomer can be added to replace the polymerizedmonomer. Such gas phase reactors can comprise a process for multi-stepgas-phase polymerization of olefins, in which olefins are polymerized inthe gaseous phase in at least two independent gas-phase polymerizationzones while feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. Representative gasphase reactors are disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790,5,436,304, 7,531,606, and 7,598,327, each of which is incorporated byreference in its entirety herein.

According to still another aspect, the polymerization reactor system cancomprise a high pressure polymerization reactor, e.g., can comprise atubular reactor or an autoclave reactor. Tubular reactors can haveseveral zones where fresh monomer, initiators, or catalysts are added.Monomer can be entrained in an inert gaseous stream and introduced atone zone of the reactor. Initiators, catalysts, and/or catalystcomponents can be entrained in a gaseous stream and introduced atanother zone of the reactor. The gas streams can be intermixed forpolymerization. Heat and pressure can be employed appropriately toobtain optimal polymerization reaction conditions.

According to yet another aspect, the polymerization reactor system cancomprise a solution polymerization reactor wherein the monomer/comonomerare contacted with the catalyst composition by suitable stirring orother means. A carrier comprising an inert organic diluent or excessmonomer can be employed. If desired, the monomer/comonomer can bebrought in the vapor phase into contact with the catalytic reactionproduct, in the presence or absence of liquid material. Thepolymerization zone can be maintained at temperatures and pressures thatwill result in the formation of a solution of the polymer in a reactionmedium. Agitation can be employed to obtain better temperature controland to maintain uniform polymerization mixtures throughout thepolymerization zone. Adequate means are utilized for dissipating theexothermic heat of polymerization.

The polymerization reactor system can further comprise any combinationof at least one raw material feed system, at least one feed system forcatalyst or catalyst components, and/or at least one polymer recoverysystem. Suitable reactor systems can further comprise systems forfeedstock purification, catalyst storage and preparation, extrusion,reactor cooling, polymer recovery, fractionation, recycle, storage,loadout, laboratory analysis, and process control. Depending upon thedesired properties of the olefin polymer, hydrogen can be added to thepolymerization reactor as needed (e.g., continuously, pulsed, etc.).

Polymerization conditions that can be controlled for efficiency and toprovide desired polymer properties can include temperature, pressure,and the concentrations of various reactants. Polymerization temperaturecan affect catalyst productivity, polymer molecular weight, andmolecular weight distribution. Various polymerization conditions can beheld substantially constant, for example, for the production of aparticular grade of the olefin polymer (or ethylene polymer). A suitablepolymerization temperature can be any temperature below thede-polymerization temperature according to the Gibbs Free energyequation. Typically, this includes from about 60° C. to about 280° C.,for example, or from about 60° C. to about 120° C., depending upon thetype of polymerization reactor(s). In some reactor systems, thepolymerization temperature generally can be within a range from about70° C. to about 100° C., or from about 75° C. to about 95° C.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than 1000 psig (6.9 MPa). Pressure forgas phase polymerization is usually at about 200 to 500 psig (1.4 MPa to3.4 MPa). High pressure polymerization in tubular or autoclave reactorsis generally run at about 20,000 to 75,000 psig (138 to 517 MPa).Polymerization reactors can also be operated in a supercritical regionoccurring at generally higher temperatures and pressures. Operationabove the critical point of a pressure/temperature diagram(supercritical phase) can offer advantages to the polymerizationreaction process.

Olefin monomers that can be employed with catalyst compositions andpolymerization processes of this invention typically can include olefincompounds having from 2 to 30 carbon atoms per molecule and having atleast one olefinic double bond, such as ethylene or propylene. In anaspect, the olefin monomer can comprise a C₂-C₂₀ olefin; alternatively,a C₂-C₂₀ alpha-olefin; alternatively, a C₂-C₁₀ olefin; alternatively, aC₂-C₁₀ alpha-olefin; alternatively, the olefin monomer can compriseethylene; or alternatively, the olefin monomer can comprise propylene(e.g., to produce a polypropylene homopolymer or a propylene-basedcopolymer).

When a copolymer (or alternatively, a terpolymer) is desired, the olefinmonomer and the olefin comonomer independently can comprise, forexample, a C₂-C₂₀ alpha-olefin. In some aspects, the olefin monomer cancomprise ethylene or propylene, which is copolymerized with at least onecomonomer (e.g., a C₂-C₂₀ alpha-olefin, a C₃-C₂₀ alpha-olefin, etc.).According to one aspect of this invention, the olefin monomer used inthe polymerization process can comprise ethylene. In this aspect, thecomonomer can comprise a C₃-C₁₀ alpha-olefin; alternatively, thecomonomer can comprise 1-butene, 1-pentene, 1-hexene, 1-octene,1-decene, styrene, or any combination thereof; alternatively, thecomonomer can comprise 1-butene, 1-hexene, 1-octene, or any combinationthereof; alternatively, the comonomer can comprise 1-butene;alternatively, the comonomer can comprise 1-hexene; or alternatively,the comonomer can comprise 1-octene.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maysuggest themselves to one of ordinary skill in the art without departingfrom the spirit of the present invention or the scope of the appendedclaims.

Melt index (MI, g/10 min) was determined in accordance with ASTM D1238at 190° C. with a 2,160 gram weight, and high load melt index (HLMI,g/10 min) was determined in accordance with ASTM D1238 at 190° C. with a21,600 gram weight. Density was determined in grams per cubic centimeter(g/cm³) on a compression molded sample, cooled at 15° C. per hour, andconditioned for 40 hours at room temperature in accordance with ASTMD1505 and ASTM D4703.

Molecular weights and molecular weight distributions were obtained usinga PL-GPC 220 (Polymer Labs, an Agilent Company) system equipped with aIR4 detector (Polymer Char, Spain) and three Styragel HMW-6E GPC columns(Waters, Mass.) running at 145° C. The flow rate of the mobile phase1,2,4-trichlorobenzene (TCB) containing 0.5 g/L2,6-di-t-butyl-4-methylphenol (BHT) was set at 1 mL/min, and polymersolution concentrations were in the range of 1.0-1.5 mg/mL, depending onthe molecular weight. Sample preparation was conducted at 150° C. fornominally 4 hr with occasional and gentle agitation, before thesolutions were transferred to sample vials for injection. An injectionvolume of about 400 μL was used. The integral calibration method wasused to deduce molecular weights and molecular weight distributionsusing a Chevron Phillips Chemical Company's HDPE polyethylene resin,MARLEX®BHB5003, as the standard. The integral table of the standard waspre-determined in a separate experiment with SEC-MALS. Mn is thenumber-average molecular weight, Mw is the weight-average molecularweight, Mz is the z-average molecular weight, and Mp is the peakmolecular weight (location, in molecular weight, of the highest point ofthe molecular weight distribution curve). The IB parameter wasdetermined from the molecular weight distribution curve (plot ofdW/d(Log M) vs. Log M; normalized to an area equal to 1), and is definedas 1/[dW/d(Log M)]_(MAX).

Melt rheological characterizations were performed as follows.Small-strain (less than 10%) oscillatory shear measurements wereperformed on an Anton Paar MCR rheometer using parallel-plate geometry.All rheological tests were performed at 190° C. The complex viscosity|η*| versus frequency (ω) data were then curve fitted using the modifiedthree parameter Carreau-Yasuda (CY) empirical model to obtain the zeroshear viscosity−η₀, characteristic viscous relaxation time−τ_(η), andthe breadth parameter−α (CY-a parameter). The simplified Carreau-Yasuda(CY) empirical model is as follows.

${{{\eta^{*}(\omega)}} = \frac{\eta_{0}}{\left\lbrack {1 + \left( {\tau_{\eta}\omega} \right)^{a}} \right\rbrack^{{({1 - n})}/a}}},$wherein: |η*(ω)|=magnitude of complex shear viscosity;

-   -   η₀=zero shear viscosity;    -   τ_(η)=viscous relaxation time (Tau(η));    -   α=“breadth” parameter (CY-a parameter);    -   n=fixes the final power law slope, fixed at 2/11; and    -   ω=angular frequency of oscillatory shearing deformation.

Details of the significance and interpretation of the CY model andderived parameters can be found in: C. A. Hieber and H. H. Chiang,Rheol. Acta, 28, 321 (1989); C. A. Hieber and H. H. Chiang, Polym. Eng.Sci., 32, 931 (1992); and R. B. Bird, R. C. Armstrong and O. Hasseger,Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, 2nd Edition,John Wiley & Sons (1987); each of which is incorporated herein byreference in its entirety.

The ATREF procedure was as follows. Forty mg of the polymer sample and20 mL of 1,2,4-trichlorobenzene (TCB) were sequentially charged into avessel on a PolyChar TREF 200+instrument. After dissolving the polymer,an aliquot (500 microliters) of the polymer solution was loaded on thecolumn (stainless steel shots) at 150° C. and cooled at 0.5° C./min to25° C. Then, the elution was begun with a 0.5 mL/min TCB flow rate andheating at 1° C./min up to 120° C., and analyzing with an IR detector.The peak ATREF temperature is the location, in temperature, of thehighest point of the ATREF curve.

The long chain branches (LCBs) per 1,000,000 total carbon atoms of theoverall polymer were calculated using the method of Janzen and Colby (J.Mol. Struct., 485/486, 569-584 (1999), incorporated herein by referencein its entirety), from values of zero shear viscosity, η₀ (determinedfrom the Carreau-Yasuda model, described hereinabove), and measuredvalues of Mw obtained using a Dawn EOS multiangle light scatteringdetector (Wyatt).

LCB content in the high molecular weight fraction and LCB distributionwere determined using the method established by Yu, et al (Yu,DesLauriers, Rohlfing, Polymer, 2015, 46, 5165-5192, incorporated hereinby reference in its entirety). Briefly, in the SEC-MALS system, a DAWNEOS photometer (Wyatt Technology, Santa Barbara, Calif.) was attached toa Waters 150-CV plus GPC system (Milford, Mass.) or a PL-210 GPC system(Polymer Labs, an Agilent company) through a hot-transfer linecontrolled at 145° C. Degassed mobile phase 1,2,4-trichlorobenzene (TCB)containing 0.5 wt % of BHT (butylated hydroxytoluene) was pumped throughan inline filter before passing through a SEC column bank. Polymersolutions injected to the system were brought downstream to the columnsby the mobile phase for fractionation. The fractionated polymers firsteluted through the MALS photometer where light scattering signals wererecorded before passing through the differential refractive indexdetector (DRI) or an IR4 detector (Polymer Characterization SA, Spain)where their concentrations were quantified.

The DAWN EOS system was calibrated with neat toluene at room temperatureto convert the measured voltage to intensity of scattered light. Duringthe calibration, toluene was filtered with a 0.02 um filter (Whatman)and directly passed through the flowcell of the EOS system. At roomtemperature, the Rayleigh ratio is given by 1.406×10⁻⁵ cm⁻¹. A narrowpolystyrene (PS) standard (American Polymer Standards) with MW of 30,000g/mol at a concentration about 5-10 mg/mL in TCB was employed tonormalize the system at 145° C. At the given chromatographic conditions,the radius of gyration (R_(g)) of the polystyrene (PS) was estimated tobe 5.6 nm. The differential refractive index detector (DRI) wascalibrated with a known quantity of PE standard. By averaging the totalchromatographic areas of recorded chromatograms for at least fiveinjections, the DRI constant (α_(RI)) was obtained using the equationbelow (equation 1):

$\begin{matrix}{\alpha_{RI} = {\left( \frac{dn}{dc} \right){c/I_{RI}}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$where I_(RI) is the DRI detector intensity, c is the polymerconcentration, and dn/dc is the refractive index increment of PE in TCBat the measuring temperature.

At a flow rate set at 0.7 mL/min, the mobile phase was eluted throughthree (3) 7.5 mm×300 mm 20 μm mixed A columns (Polymer Labs, an Agilentcompany). PE solutions with nominal concentrations of 1.5 mg/mL wereprepared at 150° C. for 4 h. At each chromatographic slice, both theabsolute molecular weight (M) and the root mean square (RMS) radius,aka, radius of gyration, R_(g), were obtained from the Debye plots. Thelinear PE control employed was CPChem Marlex™ HiD9640, a high-density PEwith broad MWD. The refractive index increment do/dc used in this studywas 0.097 mL/g for PE dissolved in TCB at 135° C.

The Zimm-Stockmayer approach (Zimm, Stockmayer, J. Chem. Phys. 1949, 17,1301, incorporated herein by reference in its entirety) was employed todetermine the amount of LCB in the polyethylene resins. In SEC-MALS,both M and R_(g) were measured simultaneously at each slice of achromatogram. At the same molecular weight, R_(g) of a branched polymeris smaller than that of a linear polymer. The branching index (g_(M))factor is defined as the ratio of the mean square radius of gyration ofthe branched polymer to that of the linear one at the same molecularweight using equation 2,

$\begin{matrix}{g_{M} \equiv \left( \frac{\left\langle R_{g}^{2} \right\rangle_{b}}{\left\langle R_{g}^{2} \right\rangle_{l}} \right)_{M}} & {{Equation}\mspace{14mu} 2}\end{matrix}$where the subscripts b and l represent the branched and linear polymer,respectively.

The weight-average LCB per molecule (B_(3w)) was calculated usingEquation 3 using an in-house software,

$\begin{matrix}{g_{M} = {\frac{6}{B_{3w}}\left\{ {{\frac{1}{2}\left( \frac{2 + B_{3w}}{B_{3w}} \right)^{1/2}{\ln\left\lbrack \frac{{\left( {2 + B_{3w}} \right){1/2}} + {\left( B_{3w} \right){1/2}}}{{\left( {2 + B_{3w}} \right){1/2}} - {\left( B_{3w} \right){1/2}}} \right\rbrack}} - 1} \right\}}} & (3)\end{matrix}$

LCB frequency (λ_(M) _(i) , number of LCB per 1,000 total carbons) wascalculated using equation 4 using the B3w value obtained from equation3,λ_(M) _(i) =1,000×M ₀ ×B _(3w) /M _(i)  (4)where M₀ is the unit molecular weight of polyethylene, M_(i) is themolecular weight of the i^(th) slice.

Since the presence of SCB in a polymer can affect its R_(g)-MWrelationship, the SCB effect was corrected before using equation 3 and 4for LCB and LCB distribution calculation for PE copolymers. To correctthe SCB effect on the branching index across the MWD, two relationshipsare needed: one is the relationship between the branching-indexcorrection factor (Δg_(M)) and the SCB content (x_(SCB)), and the otheris the relationship between SCB content and molecular weight, both ofwhich were determined experimentally. Mathematically, the product ofthese two relationships gives the branching index correction factor(Δg_(M)) as a function of MW, as shown in equation 5,

$\begin{matrix}{\frac{d\left( {\Delta g_{M}} \right)}{d(M)} = {\frac{d\left( x_{SCB} \right)}{d(M)} \times \frac{d\left( {\Delta\; g_{M}} \right)}{d\left( x_{SCB} \right)}}} & (5)\end{matrix}$where x_(SCB) is the SCB content (i.e., number of SCB per 1,000 totalcarbons) of the copolymer in question.

To establish the relationship between Δg_(M) and x_(SCB), PE standardsthat met the following criteria were used: the standards containessentially no LCB and have flat SCB distribution and known SCBcontents. At least five SCB standards were used for the SCB effectcorrection. The SCB content for these SCB standards ranged from 0 to 34SCB/1,000 total carbon atoms.

Short chain branch content and short chain branching distribution (SCBD)across the molecular weight distribution were determined via anIR5-detected GPC system (IR5-GPC), wherein the GPC system was a PL220GPC/SEC system (Polymer Labs, an Agilent company) equipped with threeStyragel HMW-6E columns (Waters, Mass.) for polymer separation. Athermoelectric-cooled IR5 MCT detector (IR5) (Polymer Char, Spain) wasconnected to the GPC columns via a hot-transfer line. Chromatographicdata was obtained from two output ports of the IR5 detector. First, theanalog signal goes from the analog output port to a digitizer beforeconnecting to Computer “A” for molecular weight determinations via theCirrus software (Polymer Labs, now an Agilent Company) and the integralcalibration method using a HDPE Marlex™ BHB5003 resin (Chevron PhillipsChemical) as the molecular weight standard. The digital signals, on theother hand, go via a USB cable directly to Computer “B” where they arecollected by a LabView data collection software provided by PolymerChar. Chromatographic conditions were set as follows: column oventemperature of 145° C.; flowrate of 1 mL/min; injection volume of 0.4mL; and polymer concentration of about 2 mg/mL, depending on samplemolecular weight. The temperatures for both the hot-transfer line andIR5 detector sample cell were set at 150° C., while the temperature ofthe electronics of the IR5 detector was set at 60° C. Short chainbranching content was determined via an in-house method using theintensity ratio of CH₃ (I_(CH3)) to CH₂ (I_(CH2)) coupled with acalibration curve. The calibration curve was a plot of SCB content(x_(SCB)) as a function of the intensity ratio of Imam. To obtain acalibration curve, a group of polyethylene resins (no less than 5) ofSCB level ranging from zero to ca. 32 SCB/1,000 total carbons (SCBStandards) were used. All these SCB Standards have known SCB levels andflat SCBD profiles pre-determined separately by NMR and thesolvent-gradient fractionation coupled with NMR (SGF-NMR) methods. UsingSCB calibration curves thus established, profiles of short chainbranching distribution across the molecular weight distribution wereobtained for resins fractionated by the IR5-GPC system under exactly thesame chromatographic conditions as for these SCB standards. Arelationship between the intensity ratio and the elution volume wasconverted into SCB distribution as a function of MWD using apredetermined SCB calibration curve (i.e., intensity ratio ofI_(CH3)/I_(CH2) vs. SCB content) and MW calibration curve (i.e.,molecular weight vs. elution time) to convert the intensity ratio ofI_(CH3)/I_(CH2) and the elution time into SCB content and the molecularweight, respectively.

Extensional viscosity was measured on a rotational rheometer (PhysicaMCR-500, Anton Paar) using the extensional viscosity fixture, aSentimanat Extensional Rheometer (model SER-3 universal testingplatform, Xpansion Instruments). The SER attachment makes it possible toeasily measure the transient extensional viscosity as a function oftime.

Test samples were prepared via compression molding at 182° C. Thepellets samples were allowed to melt at a relatively low pressure for 1min and then subjected to a high molding pressure for additional 2 min.Then, the hot press was turned off for slow cooling. The cooled plaquewas retrieved from the press on the following day. Rectangular stripswith dimensions of 12.77×18 mm were cut out of the molded plaque, andthe thickness of the sample was measured.

The SER testing platform has two drums that rotate in the opposingdirection (M. L. Sentmanat, “Miniature universal testing platform: fromextensional melt rheology to solid-state deformation behavior,” Rheol.Acta 43, 657 (2004); M. L. Sentmanat, B. N. Wang, G. H. McKinley,“Measuring the transient extensional rheology of polyethylene meltsusing the SER universal testing platform,” J. Rheol. 49, 585 (2005);both incorporated herein by reference in their entirety). Therectangular samples were tested by clipping onto the two posts of thefixture, then closing the oven to heat to 150° C., where it was annealedat 150° C. for 30 sec to allow the temperature to reach equilibrium. Thesample was then stretched at constant Hencky strain rates {dot over(ε)}_(H) between 0.03 and 25 s⁻¹ at 150° C. The torque M resulting fromthe force of tangential stretching of the sample between the rotatingdrums F was recorded by the rotational rheometer:M(t)=2RF(t)  (A)where the radius of drums R=5.155 mm. The Hencky strain rate {dot over(ε)}_(H) at constant drum rotating speed Ω is

$\begin{matrix}{{\overset{.}{ɛ}}_{H} = \frac{2\Omega R}{L}} & (B)\end{matrix}$where the length of the stretching zone between the rotating drumsL=12.72 mm. The transient extensional viscosity η_(E) ⁺(t) was obtainedfor given Hencky strain rate as

$\begin{matrix}{{\eta_{E}^{+}(t)} = {\frac{\sigma_{E}(t)}{{\overset{.}{ɛ}}_{E}} = \frac{F(t)}{{A\left( {t,T} \right)}{\overset{.}{ɛ}}_{E}}}} & (C)\end{matrix}$where A(t,T) is the cross-sectional area of the sample which thermallyexpands upon melting and exponentially decreases with stretching:

$\begin{matrix}{{A\left( {t,T} \right)} = {A_{o}{\exp\left( {{- {\overset{.}{ɛ}}_{E}}t} \right)}\left( \frac{\rho_{s}}{\rho(T)} \right)^{2/3}}} & (D)\end{matrix}$where A₀ and ρ_(s) are the initial cross-sectional area and the densityof the sample measured at room temperature in solid state. The meltdensity ρ(T) is given by ρ(T)=ρ₀−Δρ(T−273.1.5)T. Therefore, thetransient extensional viscosity (t) as a function of time was calculatedat each extension rate as

$\begin{matrix}{{\eta_{E}^{+}(t)} = {\frac{M - M_{{offse}t}}{2R\;{\overset{.}{ɛ}}_{E}A_{0}{\exp\left( {{- {\overset{.}{ɛ}}_{E}}t} \right)}}\left( \frac{\rho(T)}{\rho_{s}} \right)^{2/3}}} & (E)\end{matrix}$where M_(offset) is a pre-set torque which can be applied prior to theactual test. To compare the extensional response to the linearviscoelastic (LVE) limit, the LVE envelop 3η⁺(t) was obtained from therelaxation spectrum of the dynamic frequency sweep data measured at 150°C. as

$\begin{matrix}{{\eta^{+}(t)} = {\sum\limits_{i = 1}^{N}{G_{i}{\lambda_{i}\left\lbrack {1 - {\exp\left( {{- t}/\lambda_{i}} \right)}} \right\rbrack}}}} & (F)\end{matrix}$where the set of G_(i) and λ_(i) define the relaxation spectrum of thematerial.

In general, it has been observed that when long chain branching existsin the polymer, the transient extensional viscosity deviates from theLVE drastically by increasing slope just before breakage. This behavioris called the strain hardening. In contrast, for linear resins thetransient extensional viscosity growth curves show no strain hardeningby continuing to follow the LVE envelop (3η⁺(t)) according to theTrouton's rule.

Machine direction (MD) and transverse direction (TD) Elmendorf tearstrengths (g/mil) were measured on a Testing Machines Inc. tear tester(Model 83-11-00) in accordance with ASTM D1922. Film haze (%) wasdetermined in accordance with ASTM D1003.

Metals content, such as the amount of catalyst residue in the ethylenepolymer or film (on a ppm basis), can be determined by ICP analysis on aPerkinElmer Optima 8300 instrument. Polymer samples can be ashed in aThermolyne furnace with sulfuric acid overnight, followed by aciddigestion in a HotBlock with HCl and HNO₃ (3:1 v:v).

Fluorided silica-coated alumina activator-supports (FSCA) were preparedas follows. Bohemite was obtained from W.R. Grace & Company under thedesignation “Alumina A” and having a surface area of 300 m²/g, a porevolume of 1.3 mL/g, and an average particle size of 100 microns. Thealumina was first calcined in dry air at about 600° C. for approximately6 hours, cooled to ambient temperature, and then contacted withtetraethylorthosilicate in isopropanol to equal 25 wt. % SiO₂. Afterdrying, the silica-coated alumina was calcined at 600° C. for 3 hours.Fluorided silica-coated alumina (7 wt. % F) was prepared by impregnatingthe calcined silica-coated alumina with an ammonium bifluoride solutionin methanol, drying, and then calcining for 3 hours at 600° C. in dryair. Afterward, the fluorided silica-coated alumina (FSCA) was collectedand stored under dry nitrogen, and was used without exposure to theatmosphere.

Examples 1-12

Comparative Example 11 was a commercially-availablemetallocene-catalyzed medium density ethylene copolymer resin fromChevron-Phillips Chemical Company LP, and Comparative Example 12 was acommercially-available chromium-catalyzed medium density ethylenecopolymer resin from Chevron-Phillips Chemical Company LP.

The polymerization experiments of Examples 1-10 were conducted for 30-60min in a one-gallon or five-gallon stainless-steel autoclave reactorcontaining isobutane as diluent, and hydrogen added from a 325-ccauxiliary vessel. Table I summarizes certain polymerization conditionsfor Examples 1-10. Generally, solutions of the metallocene compoundswere prepared by dissolving approximately 20 mg total of the catalystcomponent I and catalyst component II metallocenes in 20 mL of toluene.Under an isobutane purge, TIBA (1M in heptanes), the FSCA, and themetallocene solutions were charged in that order to a cold reactorthrough a charge port. The reactor was closed, and isobutane was added.The reactor was heated to the desired run temperature of 80° C., and1-hexene and ethylene were then introduced into the reactor (hydrogenwas not used). Ethylene was fed on demand to maintain the targetpressure of 320 or 350 psig. The reactor was maintained at the desiredtemperature throughout the experiment by an automated heating-coolingsystem. After venting of the reactor, purging, and cooling, theresulting polymer product was dried at 50° C. under reduced pressure.The structures for the metallocene compounds used in Examples 1-10 areshown below (Et=ethyl; Pr=propyl):

Cast film samples at a 1-mil thickness (25 microns) were produced fromthe polymers of Examples 8-10 on a laboratory-scale cast film line usingtypical linear low density polyethylene conditions (LLDPE) as follows:152 mm die width, 0.508 mm die gap, 16 mm diameter single-screw extruder(L/D=24-27), 0.5 kg/hr output rate, and 204° C. barrel and die settemperatures. Cooling was accomplished with chill roll at about 23° C.These particular processing conditions were chosen because the cast filmproperties so obtained are typically representative of those obtainedfrom larger, commercial scale film casting conditions.

Blown film samples at a 1-mil thickness (25 microns) were produced fromthe polymer of Example 11 on a laboratory-scale blown film line usingtypical linear low density polyethylene conditions (LLDPE) as follows:100 mm die diameter, 1.5 mm die gap, 37.5 mm diameter single-screwextruder fitted with a barrier screw with a Maddock mixing section atthe end (L/D=24, 2.2:1 compression ratio), 27 kg/hr output rate, 2.5:1blow-up ratio (BUR), “in-pocket” bubble with a “frost line height” (FLH)of about 28 cm, and 190° C. barrel and die set temperatures. Cooling wasaccomplished with a Dual Lip air ring using ambient (laboratory) air atabout 25° C. These particular processing conditions were chosen becausethe blown film properties so obtained are typically representative ofthose obtained from larger, commercial scale film blowing conditions.

For the polymers of Examples 1-12, Table II summarizes various meltindex, density, rheology, and LCB (Janzen-Colby) properties, while TableIII summarizes molecular weight properties. FIG. 1 illustrates themolecular weight distribution curves (amount of polymer versus thelogarithm of molecular weight) for the polymers of Examples 1, 3, and11-12, while FIG. 2 illustrates the molecular weight distribution curvesfor the polymers of Examples 8-10. Generally, the polymers of Examples1-10 had densities in the 0.92-0.94 g/cm³ range, melt index values inthe 0-10 g/10 min range, ratios of Mw/Mn in the 3-6 range, ratios ofMz/Mw in the 2-4 range, CY-a parameters in the 0.3-0.6 range, lowrelaxation times of less than 0.1 sec, and overall LCB contents(Janzen-Colby) in the 1-7 LCB range (per 1,000,000 carbon atoms).

FIGS. 3-5 illustrate the short chain branch distributions for thepolymers of Examples 2, 3, and 5, respectively, and these curves arerepresentative of the other ethylene polymers produced in the inventiveexamples. Surprisingly, these polymers have a conventional SCBD (e.g.,similar to chromium-based polymers), in which the SCB content generallydecreases with increasing molecular weight.

FIG. 6 illustrates the ATREF profiles of the polymers of Examples 8-11,and certain information from the ATREF profiles is summarized in TableIV. ATREF profiles of Examples 8-10 had single peaks at peak ATREFtemperatures in the 90-95° C. range, with only 60-75 wt. % of thepolymer eluting above 86° C., and much higher amounts of polymer elutedbelow 40° C. and in the 40-76° C. range, as compared to themetallocene-based polymer of Comparative Example 11.

FIG. 7 illustrates an extensional viscosity plot at 190° C. for thepolymer of Example 10, FIG. 8 summarizes the maximum ratio of η_(E)/3ηat extensional rates in the 0.03 to 10 sec⁻¹ range for the polymers ofExamples 3 and 8-10, and FIG. 9 illustrates the long chain branchdistribution across the molecular weight distribution of the polymer ofExample 3, and these figures are representative of the other ethylenepolymers produced in the inventive examples. The purpose of thesefigures was to ascertain the amount of LCBs and where it resides withinthe molecular weight distribution. As shown in Table II, the overall LCBcontents (via the Janzen-Colby method) were in the 1-7 LCB range (per1,000,000 carbon atoms). However, this method does not determine wherethe LCBs reside within the molecular weight distribution. Typically, thelong chain branching is present in the high molecular weight fractionfor single metallocene polymers, but unexpectedly, for the polymers ofExample 1-10, this is not the case. There is substantially no long chainbranching in the high molecular weight fraction—i.e., an average numberof long chain branches (LCBs) per 1,000,000 total carbon atoms of thepolymer in the molecular weight range of 500,000 to 2,000,000 g/mol isless than or equal to about 5.

FIG. 9 shows virtually no long chain branching in the high molecularweight fraction. The average number of LCBs per 1,000,000 total carbonatoms in the molecular weight range of 500,000 to 2,000,000 g/mol was0.87 (i.e., less than 1 LCB per 1,000,000 total carbon atoms in the500,000-2,000,000 g/mol range). This average LCB content was calculatedfrom Equation 6 below.

$\begin{matrix}{\overset{\_}{\lambda} = \frac{\sum\limits_{{MW} = {2000{{kg}/{mol}}}}^{{MW} = {500{{kg}/{{mo}l}}}}{{\lambda_{i}\left( \frac{dw}{d\left( {LogM} \right)} \right)}_{i}\left( {d\left( {{Lo}gM} \right)} \right)_{i}}}{\sum\limits_{{MW} = {2000{{kg}/{mol}}}}^{{MW} = {500{{kg}/{{mo}l}}}}{{\lambda_{i}\left( \frac{dw}{d\left( {LogM} \right)} \right)}_{i}\left( {d\left( {{Lo}gM} \right)} \right)_{i}}}} & {{Equation}\mspace{14mu} 6}\end{matrix}$

where λ is the number-average LCB number in the molecular weight rangeof 500,000 to 2,000,000 g/mol and λ_(i) is LCB at slice i.

It was desired that the presence of LCBs in lower molecular weightportions of the polymer could be quantified using this SEC-MALStechnique. However, the numerous data points centered around a molecularweight of 100,000 g/mol in FIG. 9 have too much error for reliablequantification; the measured signal and the baseline/background are toosimilar at these lower molecular weights.

Extensional rheology, therefore, was used as a means to quantify theamount of LCBs in the lower molecular weight portion of the molecularweight distribution. For a Newtonian fluid, the ratio of extensionalviscosity will be equal to 3 times the shear viscosity; the ratio ofη_(E)/3η will be equal to 1 for a Newtonian fluid. For molten polymerswith strain hardening due to the presence of LCBs, the ratio of η_(E)/3ηwill be greater than 1. FIG. 7 illustrates an extensional viscosity plotat 190° C. for the polymer of Example 10, determined using SER. Theminor scatter in the baseline was due to the limited amount of samplesfor the SER experiments. From FIG. 7 and similar plots for Examples 3and 8-9, FIG. 8 was prepared to summarize the maximum ratio of η_(E)/3ηat extensional rates in the 0.03 to 10 sec⁻¹ range for the polymers ofExamples 3 and 8-10. A higher ratio equates to more strain hardening,and therefore, higher levels of LCBs. For these inventive polymers,unexpectedly, the maximum ratio of η_(E)/3η at the extensional rate of0.03 sec⁻¹ ranged from 6 to 10, and ranged from 3 to 7 at an extensionalrate of 0.1 sec⁻¹. Thus, despite there being substantially no long chainbranching in the high molecular weight fraction of the inventivepolymers, beneficially, there was a significant amount of long chainbranching in the lower molecular weight fraction of the polymers, suchthat polymer melt strength and bubble stability in blown film and otherapplications is sufficient.

Table V summarizes tear resistance and optical properties of the filmsof Examples 8-10 and Comparative Example 11. Unexpectedly, the presenceof LCBs only in the lower molecular weight fraction resulted in MDElmendorf tear strengths that were much superior to that of standardmetallocene-catalyzed Example 11. Also, the tear resistance improvedwith no sacrifice in optical properties; film haze was comparable forthese examples.

Thus, the ethylene copolymers disclosed herein offer a beneficialcombination of density, molecular weight, melt flow, LCB, SCB, and ATREFproperties, resulting in improved processability and melt strength (orbubble stability). Film products produced from these copolymers haveexcellent optical properties and improved tear resistance, particularlyin the machine direction, as quantified by the MD Elmendorf tearstrength.

TABLE I Examples 1-10 - Polymerization Experiments at 80° C. MET-1 MET-2FSCA Pressure 1-Hexene Time Polymer Example (mg) (mg) (g) (psig) (g)(min) (g) One-gallon polymerization reactor 1 0.05 1 0.09 320 40 30 75 20.1 1 0.11 320 40 30 101 3 0.15 1 0.10 320 40 30 88 4 0.2 1 0.10 320 4030 76 Five-gallon polymerization reactor 5 1 6 0.25 350 100 30 1828 60.7 4.8 0.21 350 120 30 2275 7 0.5 3 0.12 350 150 60 2319 8 0.25 3 0.11350 200 45 1435 9 0.25 3 0.16 350 220 30 2118 10 0.2 3 0.13 350 250 302006

TABLE II Examples 1-12 - Polymer Properties. LCBs per MI HLMI Density η₀τ_(η) 1,000,000 Example (g/10 min) (g/10 min) (g/cc) (Pa-sec) (sec) CY-acarbon atoms 1 0.01 0 0.926 53430 0.0928 0.343 2.6 2 0.09 7 0.928 280500.0465 0.336 2.5 3 0.41 31 0.929 7230 0.0140 0.348 2.5 4 3.80 114 0.9291110 0.0040 0.422 2.9 5 2.11 — 0.941 3670 0.0078 0.514 1.9 6 3.40 —0.940 2850 0.0072 0.515 1.4 7 9.17 245 0.941 1150 0.0026 0.452 2.9 82.31 73 0.932 5140 0.0097 0.415 6.5 9 2.56 — 0.936 3690 0.0085 0.424 3.810 1.11 — 0.930 9260 0.0188 0.427 2.0 11 0.9 — 0.933 7240 0.0112 0.5231.0 12 0.2 — 0.955 607000 1.67 0.157 26.9

TABLE III Examples 1-12 - Molecular Weight Properties. Mn/1000 Mw/1000Mz/1000 Mp/1000 Example (g/mol) (g/mol) (g/mol) (g/mol) IB Mw/Mn Mz/Mw 137.2 184.3 519.8 129.3 1.21 4.96 2.82 2 32.4 161.7 447.3 116.8 1.21 5.002.77 3 22.8 118.7 354.6 91.8 1.34 5.21 2.99 4 13.6 73.4 266.4 19.0 1.625.40 3.63 5 26.7 103.0 247.9 95.0 1.24 3.86 2.41 6 24.0 98.6 247.7 92.71.31 4.11 2.51 7 19.1 74.1 213.9 52.1 1.38 3.88 2.89 8 19.1 95.5 296.793.8 1.49 5.00 3.11 9 18.6 96.3 277.6 79.7 1.35 5.18 2.88 10 24.9 129.5366.9 99.9 1.22 5.19 2.83 11 55.7 129.0 232.6 103.1 0.94 2.32 1.80 1218.0 133.9 833.8 45.1 1.55 7.44 6.23

TABLE IV Examples 8-11 - ATREF Properties. <40° C. 40-76° C. 76-86°C. >86° C. Peak Temp. Example (wt. %) (wt. %) (wt. %) (wt. %) (° C.) 83.9 21.3 12.5 62.3 93.6 9 2.0 20.2 7.2 70.6 93.6 10 3.5 16.7 14.9 64.993.9 11 0.4 0.2 3.3 96.1 95.6

TABLE V Examples 8-11 - Film Properties. Tear MD Tear TD Tear Ratio HazeExample (g/mil) (g/mil) MD/TD (%) 8 100 261 0.38 8.8 9 51 123 0.41 8.310 132 511 0.26 7.0 11 36 549 0.07 6.8

The invention is described above with reference to numerous aspects andspecific examples. Many variations will suggest themselves to thoseskilled in the art in light of the above detailed description. All suchobvious variations are within the full intended scope of the appendedclaims. Other aspects of the invention can include, but are not limitedto, the following (aspects are described as “comprising” but,alternatively, can “consist essentially of” or “consist of”):

Aspect 1. An ethylene polymer having:

-   -   a melt index in a range from 0 to about 15 g/10 min;    -   a density in a range from about 0.91 to about 0.945 g/cm³;    -   a CY-a parameter at 190° C. in a range from about 0.2 to about        0.6;    -   an average number of long chain branches (LCBs) per 1,000,000        total carbon atoms of the polymer in a molecular weight range of        500,000 to 2,000,000 g/mol of less than or equal to about 5; and    -   a maximum ratio of η_(E)/3η at an extensional rate of 0.03 sec⁻¹        in a range from about 3 to about 15.

Aspect 2. The polymer defined in aspect 1, wherein the ethylene polymerhas a melt index (MI) in any range disclosed herein, e.g., from 0 toabout 15 g/10 min, from about 0.1 to about 10 g/10 min, from about 0.2to about 5 g/10 min, from about 0.4 to about 4 g/10 min, from about 0.75to about 2.75 g/10 min. etc.

Aspect 3. The polymer defined in aspect 1 or 2, wherein the ethylenepolymer has a high load melt index (HLMI) in any range disclosed herein,e.g., from 0 to about 300 g/10 min, from about 5 to about 100 g/10 min,from about 25 to about 75 g/10 min, etc.

Aspect 4. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a ratio of HLMI/MI in any rangedisclosed herein, e.g., from about 15 to about 90, from about 20 toabout 80, from about 20 to about 40, etc.

Aspect 5. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a density in any range disclosedherein, e.g., from about 0.91 to about 0.94 g/cm³, from about 0.92 toabout 0.945 g/cm³, from about 0.92 to about 0.94 g/cm³, from about 0.925to about 0.945 g/cm³, from about 0.922 to about 0.942 g/cm³, etc.

Aspect 6. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a CY-a parameter in any range disclosedherein, e.g., from about 0.25 to about 0.55, from about 0.3 to about0.6, from about 0.3 to about 0.55, from about 0.32 to about 0.52, etc.

Aspect 7. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a number of short chain branches (SCBs)per 1000 total carbon atoms of the polymer at Mn that is greater than atMz, and/or a number of short chain branches (SCBs) per 1000 total carbonatoms of the polymer at Mn that is greater than at Mw, and/or a numberof short chain branches (SCBs) per 1000 total carbon atoms of thepolymer at Mw that is greater than at Mz (a conventional short chainbranching distribution or decreasing comonomer distribution).

Aspect 8. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has an average number of long chainbranches (LCBs) per 1,000,000 total carbon atoms of the polymer in themolecular weight range of 500,000 to 2,000,000 g/mol in any rangedisclosed herein, e.g., less than or equal to about 4, less than orequal to about 3, less than or equal to about 2, less than or equal toabout 1, etc.

Aspect 9. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a maximum ratio of η_(E)/3η at anextensional rate of 0.03 sec⁻¹ in any range disclosed herein, e.g., fromabout 3 to about 10, from about 4 to about 15, from about 4 to about 12,from about 4 to about 10, from about 5 to about 9, etc.

Aspect 10. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a maximum ratio of η_(E)/3η at anextensional rate of 0.1 sec⁻¹ in any range disclosed herein, e.g., fromabout 2 to about 10, from about 2 to about 8, from about 2 to about 6,from about 3 to about 9, from about 3 to about 7, etc.

Aspect 11. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer contains from about 1 to about 10 LCBs,from about 1 to about 8 LCBs, from about 1 to about 7 LCBs, etc., per1,000,000 total carbon atoms.

Aspect 12. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a ratio of Mw/Mn in any range disclosedherein, e.g., from about 3 to about 10, from about 3.5 to about 8, fromabout 3 to about 6, from about 3.5 to about 6, etc.

Aspect 13. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a ratio of Mz/Mw in any range disclosedherein, e.g., from about 2 to about 5, from about 2 to about 4.5, fromabout 2.2 to about 5, from about 2.2 to about 4, etc.

Aspect 14. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a Mz in any range disclosed herein,e.g., from about 150,000 to about 600,000 g/mol, from about 200,000 toabout 550,000 g/mol, from about 200,000 to about 500,000 g/mol, fromabout 220,000 to about 450,000 g/mol, etc.

Aspect 15. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a Mw in any range disclosed herein,e.g., from about 50,000 to about 250,000 g/mol, from about 60,000 toabout 200,000 g/mol, from about 70,000 to about 185,000 g/mol, fromabout 65,000 to about 175,000 g/mol, from about 80,000 to about 140,000g/mol, etc.

Aspect 16. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a Mn in any range disclosed herein,e.g., from about 10,000 to about 50,000 g/mol, from about 10,000 toabout 40,000 g/mol, from about 10,000 to about 38,000 g/mol, from about12,000 to about 30,000 g/mol, etc.

Aspect 17. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has an IB parameter in any range disclosedherein, e.g., from about 1 to about 2, from about 1 to about 1.7, fromabout 1.1 to about 1.8, from about 1.15 to about 1.75, etc.

Aspect 18. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a zero-shear viscosity in any rangedisclosed herein, e.g., from about 1000 to about 1,000,000 Pa-sec, fromabout 1000 to about 50,000 Pa-sec, from about 2000 to about 10,000Pa-sec, etc.

Aspect 19. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has a relaxation time in any rangedisclosed herein, e.g., from about 0.001 to about 0.15 sec, from about0.002 to about 0.1 sec, from about 0.002 to about 0.025 sec, etc.

Aspect 20. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has an ATREF profile characterized by apeak ATREF temperature in any range disclosed herein, e.g., from about85 to about 100° C., from about 88 to about 98° C., from about 90 toabout 96° C., etc.

Aspect 21. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer has an ATREF profile characterized by fromabout 0.5 to about 6 wt. % (or from about 1 to about 5 wt. %, or fromabout 1.5 to about 4.5 wt. %) of the polymer eluting below a temperatureof 40° C., by from about 12 to about 26 wt. % (or from about 13 to about24 wt. %, or from about 14 to about 23 wt. %) of the polymer elutingbetween 40 and 76° C., by from about 52 to about 82 wt. % (or from about55 to about 80 wt. %, or from about 58 to about 75 wt. %) of the polymereluting above a temperature of 86° C., and the remainder of the polymer(to reach 100 wt. %) eluting between 76 and 86° C.

Aspect 22. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer is a single reactor product, e.g., not apost-reactor blend of two polymers, for instance, having differentmolecular weight characteristics.

Aspect 23. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer comprises an ethylene/α-olefin copolymerand/or an ethylene homopolymer.

Aspect 24. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer comprises an ethylene/1-butene copolymer,an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, anethylene homopolymer, or any combination thereof.

Aspect 25. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer comprises an ethylene/1-hexene copolymer.

Aspect 26. The polymer defined in any one of the preceding aspects,wherein the ethylene polymer contains, independently, less than 0.1 ppm(by weight), less than 0.08 ppm, less than 0.05 ppm, less than 0.03 ppm,etc., of chromium and titanium.

Aspect 27. The polymer defined in any one of the preceding aspects,wherein the polymer further comprises any additive disclosed herein,e.g., an antioxidant, an acid scavenger, an antiblock additive, a slipadditive, a colorant, a filler, a polymer processing aid, a UV additive,etc., or combinations thereof.

Aspect 28. An article of manufacture comprising (or produced from) theethylene polymer defined in any one of aspects 1-27.

Aspect 29. An article of manufacture comprising (or produced from) theethylene polymer defined in any one of aspects 1-27, wherein the articleis an agricultural film, an automobile part, a bottle, a container forchemicals, a drum, a fiber or fabric, a food packaging film orcontainer, a food service article, a fuel tank, a geomembrane, ahousehold container, a liner, a molded product, a medical device ormaterial, an outdoor storage product, outdoor play equipment, a pipe, asheet or tape, a toy, or a traffic barrier.

Aspect 30. A film comprising (or produced from) the ethylene polymerdefined in any one of aspects 1-27.

Aspect 31. The film defined in aspect 30, wherein the film has a haze(with or without additives) in any range disclosed herein, e.g., lessthan or equal to about 10%, less than or equal to about 9%, from about 3to about 10%, from about 4 to about 9%, from about 5 to about 10%, etc.

Aspect 32. The film defined in aspect 30 or 31, wherein the film has aMD Elmendorf tear strength in any range disclosed herein, e.g., fromabout 40 to about 250 g/mil, from about 45 to about 200 g/mil, fromabout 40 to about 150 g/mil, from about 50 to about 150 g/mil, etc.

Aspect 33. The film defined in any one of aspects 30-32, wherein thefilm has a TD Elmendorf tear strength in any range disclosed herein,e.g., from about 75 to about 600 g/mil, from about 100 to about 550g/mil, from about 120 to about 550 g/mil, etc.

Aspect 34. The film defined in any one of aspects 30-33, wherein thefilm has an average thickness in any range disclosed herein, e.g., fromabout 0.5 to about 20 mils, from about 0.5 to about 8 mils, from about0.8 to about 5 mils, from about 0.7 to about 2 mils, etc.

Aspect 35. The film defined in any one of aspects 30-34, wherein thefilm has a ratio of MD Elmendorf tear strength to TD Elmendorf tearstrength (MD:TD) in any range disclosed herein, e.g., from about 0.15:1to about 0.55:1, from about 0.2:1 to about 0.5:1, from about 0.2:1 toabout 0.45:1, from about 0.25:1 to about 0.5:1, etc.

Aspect 36. A catalyst composition comprising:

-   -   catalyst component I comprising any single atom bridged        metallocene compound disclosed herein with an indenyl group and        a cyclopentadienyl group;    -   catalyst component II comprising any unbridged hafnium        metallocene compound disclosed herein with two cyclopentadienyl        groups;    -   any activator disclosed herein; and optionally, any co-catalyst        disclosed herein.

Aspect 37. The composition defined in aspect 36, wherein the activatorcomprises an activator-support, an aluminoxane compound, an organoboronor organoborate compound, an ionizing ionic compound, or any combinationthereof.

Aspect 38. The composition defined in aspect 36, wherein the activatorcomprises an aluminoxane compound.

Aspect 39. The composition defined in aspect 36, wherein the activatorcomprises an organoboron or organoborate compound.

Aspect 40. The composition defined in aspect 36, wherein the activatorcomprises an ionizing ionic compound.

Aspect 41. The composition defined in aspect 36, wherein the activatorcomprises an activator-support, the activator-support comprising anysolid oxide treated with any electron-withdrawing anion disclosedherein.

Aspect 42. The composition defined in aspect 36, wherein the activatorcomprises fluorided alumina, chlorided alumina, bromided alumina,sulfated alumina, fluorided silica-alumina, chlorided silica-alumina,bromided silica-alumina, sulfated silica-alumina, fluoridedsilica-zirconia, chlorided silica-zirconia, bromided silica-zirconia,sulfated silica-zirconia, fluorided silica-titania, fluoridedsilica-coated alumina, fluorided-chlorided silica-coated alumina,sulfated silica-coated alumina, phosphated silica-coated alumina, or anycombination thereof.

Aspect 43. The composition defined in aspect 36, wherein the activatorcomprises fluorided alumina, sulfated alumina, fluorided silica-alumina,sulfated silica-alumina, fluorided silica-coated alumina,fluorided-chlorided silica-coated alumina, sulfated silica-coatedalumina, or any combination thereof.

Aspect 44. The composition defined in aspect 36, wherein the activatorcomprises a fluorided solid oxide and/or a sulfated solid oxide.

Aspect 45. The composition defined in any one of aspects 41-44, whereinthe activator further comprises any metal or metal ion disclosed herein,e.g., zinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, or any combination thereof.

Aspect 46. The composition defined in any one of aspects 36-45, whereinthe catalyst composition comprises a co-catalyst, e.g., any suitableco-catalyst.

Aspect 47. The composition defined in any one of aspects 36-46, whereinthe co-catalyst comprises any organoaluminum compound disclosed herein.

Aspect 48. The composition defined in aspect 47, wherein theorganoaluminum compound comprises trimethylaluminum, triethylaluminum,triisobutylaluminum, or a combination thereof.

Aspect 49. The composition defined in any one of aspects 41-48, whereinthe catalyst composition comprises catalyst component I, catalystcomponent II, a solid oxide treated with an electron-withdrawing anion,and an organoaluminum compound.

Aspect 50. The composition defined in any one of aspects 36-49, whereinat least one of the indenyl group and the cyclopentadienyl group issubstituted.

Aspect 51. The composition defined in any one of aspects 36-50, whereincatalyst component I has an unsubstituted cyclopentadienyl group and analkyl-substituted indenyl group, e.g., a C₁ to C₆ alkyl group.

Aspect 52. The composition defined in any one of aspects 36-51, whereincatalyst component I has a single carbon or silicon bridging atom.

Aspect 53. The composition defined in aspect 52, wherein the carbon orsilicon bridging atom has two substituents independently selected from Hor a C₁ to C₁₈ hydrocarbyl group, e.g., a C₁ to C₆ alkyl group.

Aspect 54. The composition defined in any one of aspects 36-53, whereincatalyst component I contains zirconium.

Aspect 55. The composition defined in any one of aspects 36-54, whereinat least one of the two cyclopentadienyl groups is substituted.

Aspect 56. The composition defined in any one of aspects 36-55, whereinthe cyclopentadienyl groups are substituted.

Aspect 57. The composition defined in any one of aspects 36-56, whereinthe substituents are the same (or different).

Aspect 58. The composition defined in any one of aspects 36-57, whereinthe two cyclopentadienyl groups are the same or different, and arealkyl-substituted cyclopentadienyl groups, e.g., a C₁ to C₆ alkyl group.

Aspect 59. The composition defined in any one of aspects 41-58, whereinthe catalyst composition is substantially free of aluminoxane compounds,organoboron or organoborate compounds, ionizing ionic compounds, orcombinations thereof.

Aspect 60. The composition defined in any one of aspects 36-59, whereina weight ratio of catalyst component I to catalyst component II in thecatalyst composition is in any range disclosed herein, e.g., from about25:1 to about 1:25, from about 10:1 to about 1:10, from about 5:1 toabout 1:5, from about 1:1 to about 1:20, from about 1:2 to about 1:10,etc.

Aspect 61. The composition defined in any one of aspects 36-60, whereinthe catalyst composition is produced by a process comprising contacting,in any order, catalyst component I, catalyst component II, and theactivator.

Aspect 62. The composition defined in any one of aspects 36-61, whereinthe catalyst composition is produced by a process comprising contacting,in any order, catalyst component I, catalyst component II, theactivator, and the co-catalyst.

Aspect 63. The composition defined in any one of aspects 36-62, whereina catalyst activity of the catalyst composition is in any rangedisclosed herein, e.g., from about 500 to about 5000, from about 750 toabout 4000, from about 1000 to about 3500 grams, etc., of ethylenepolymer per gram of activator-support per hour, under slurrypolymerization conditions, with a triisobutylaluminum co-catalyst, usingisobutane as a diluent, and with a polymerization temperature of 80° C.and a reactor pressure of 350 psig.

Aspect 64. An olefin polymerization process, the process comprisingcontacting the catalyst composition defined in any one of aspects 36-63with an olefin monomer and an optional olefin comonomer in apolymerization reactor system under polymerization conditions to producean olefin polymer.

Aspect 65. The process defined in aspect 64, wherein the olefin monomercomprises any olefin monomer disclosed herein, e.g., any C₂-Cao olefin.

Aspect 66. The process defined in aspect 64 or 65, wherein the olefinmonomer and the olefin comonomer independently comprise a C₂-C₂₀alpha-olefin.

Aspect 67. The process defined in any one of aspects 64-66, wherein theolefin monomer comprises ethylene.

Aspect 68. The process defined in any one of aspects 64-67, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising a C₃-C₁₀ alpha-olefin.

Aspect 69. The process defined in any one of aspects 64-68, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising 1-butene, 1-hexene, 1-octene, or a mixture thereof.

Aspect 70. The process defined in any one of aspects 64-66, wherein theolefin monomer comprises propylene.

Aspect 71. The process defined in any one of aspects 64-70, wherein thepolymerization reactor system comprises a batch reactor, a slurryreactor, a gas-phase reactor, a solution reactor, a high pressurereactor, a tubular reactor, an autoclave reactor, or a combinationthereof.

Aspect 72. The process defined in any one of aspects 64-71, wherein thepolymerization reactor system comprises a slurry reactor, a gas-phasereactor, a solution reactor, or a combination thereof.

Aspect 73. The process defined in any one of aspects 64-72, wherein thepolymerization reactor system comprises a loop slurry reactor.

Aspect 74. The process defined in any one of aspects 64-73, wherein thepolymerization reactor system comprises a single reactor.

Aspect 75. The process defined in any one of aspects 64-73, wherein thepolymerization reactor system comprises 2 reactors.

Aspect 76. The process defined in any one of aspects 64-73, wherein thepolymerization reactor system comprises more than 2 reactors.

Aspect 77. The process defined in any one of aspects 64-76, wherein theolefin polymer comprises any olefin polymer disclosed herein.

Aspect 78. The process defined in any one of aspects 64-69 and 71-77,wherein the olefin polymer comprises an ethylene homopolymer, anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or anethylene/1-octene copolymer.

Aspect 79. The process defined in any one of aspects 64-69 and 71-78,wherein the olefin polymer comprises an ethylene/1-hexene copolymer.

Aspect 80. The process defined in any one of aspects 64-66 and 70-77,wherein the olefin polymer comprises a polypropylene homopolymer or apropylene-based copolymer.

Aspect 81. The process defined in any one of aspects 64-80, wherein thepolymerization conditions comprise a polymerization reaction temperaturein a range from about 60° C. to about 120° C. and a reaction pressure ina range from about 200 to about 1000 psig (about 1.4 to about 6.9 MPa).

Aspect 82. The process defined in any one of aspects 64-81, wherein thepolymerization conditions are substantially constant, e.g., for aparticular polymer grade.

Aspect 83. The process defined in any one of aspects 64-82, wherein nohydrogen is added to the polymerization reactor system.

Aspect 84. The process defined in any one of aspects 64-82, whereinhydrogen is added to the polymerization reactor system.

Aspect 85. The process defined in any one of aspects 64-84, wherein theolefin polymer produced is defined in any one of aspects 1-27.

Aspect 86. An olefin polymer produced by the olefin polymerizationprocess defined in any one of aspects 64-84.

Aspect 87. An ethylene polymer defined in any one of aspects 1-27produced by the process defined in any one of aspects 64-84.

Aspect 88. An article comprising the polymer defined in any one ofaspects 85-87.

Aspect 89. A method or forming or preparing an article of manufacturecomprising an olefin polymer, the method comprising (i) performing theolefin polymerization process defined in any one of aspects 64-84 toproduce an olefin polymer (e.g., the ethylene polymer of any one ofaspects 1-27), and (ii) forming the article of manufacture comprisingthe olefin polymer, e.g., via any technique disclosed herein.

We claim:
 1. An ethylene polymer having: a melt index in a range from 0to about 15 g/10 min; a density in a range from about 0.91 to about0.945 g/cm³; a CY-a parameter at 190° C. in a range from about 0.2 toabout 0.6; an average number of long chain branches (LCBs) per 1,000,000total carbon atoms of the ethylene polymer in a molecular weight rangeof 500,000 to 2,000,000 g/mol of less than or equal to about 5; and amaximum ratio of extensional viscosity to three times shear viscosity,η_(E)/3η, at an extensional rate of 0.03 sec⁻¹ in a range from about 3to about
 15. 2. An article of manufacture comprising the ethylenepolymer of claim
 1. 3. The ethylene polymer of claim 1, wherein: theaverage number of LCBs per 1,000,000 total carbon atoms of the ethylenepolymer in the molecular weight range of 500,000 to 2,000,000 g/mol isless than or equal to about 2; and the maximum ratio of η_(E)/3η at theextensional rate of 0.03 sec⁻¹ is in a range from about 4 to about 12.4. The ethylene polymer of claim 1, wherein: the melt index is in arange from about 0.4 to about 4 g/10 min; the density is in a range fromabout 0.92 to about 0.94 g/cm³; and the CY-a parameter at 190° C. is ina range from about 0.3 to about 0.55.
 5. The ethylene polymer of claim4, wherein the ethylene polymer comprises an ethylene/1-butenecopolymer, an ethylene/1-hexene copolymer, an ethylene/1-octenecopolymer, or a combination thereof.
 6. The ethylene polymer of claim 5,wherein the ethylene polymer has a ratio of HLMI/MI in a range fromabout 20 to about
 80. 7. An article of manufacture comprising theethylene polymer of claim
 5. 8. The ethylene polymer of claim 1, whereinthe ethylene polymer has: a ratio of Mw/Mn in a range from about 3 toabout 6; and a ratio of Mz/Mw in a range from about 2 to about 4.5. 9.The ethylene polymer of claim 1, wherein the ethylene polymer has: a Mnin a range from about 10,000 to about 50,000 g/mol; a Mw in a range fromabout 50,000 to about 250,000 g/mol; and a Mz in a range from about200,000 to about 550,000 g/mol.
 10. The ethylene polymer of claim 1,wherein the ethylene polymer contains from about 1 to about 10 LCBs per1,000,000 total carbon atoms.
 11. The ethylene polymer of claim 1,wherein the ethylene polymer has a number of short chain branches (SCBs)per 1000 total carbon atoms of the ethylene polymer at Mn that isgreater than at Mz.
 12. The ethylene polymer of claim 1, wherein theethylene polymer has a maximum ratio of η_(E)/3η at an extensional rateof 0.1 sec⁻¹ in a range from about 2 to about
 10. 13. The ethylenepolymer of claim 1, wherein the ethylene polymer comprises anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, anethylene/1-octene copolymer, or a combination thereof.
 14. The ethylenepolymer of claim 13, wherein: the melt index is in a range from about0.4 to about 4 g/10 min; the density is in a range from about 0.91 toabout 0.94 g/cm³; and the CY-a parameter at 190° C. is in a range fromabout 0.3 to about 0.6.
 15. The ethylene polymer of claim 14, whereinthe ethylene polymer has: an D3 parameter in a range from about 1.1 toabout 1.8; a relaxation time in a range from about 0.002 to about 0.025sec.
 16. The ethylene polymer of claim 14, wherein the ethylene polymerhas an ATREF profile characterized by: a peak ATREF temperature in arange from about 88 to about 98° C.; from about 0.5 to about 6 wt % ofthe ethylene polymer eluting below a temperature of 40° C.; from about12 to about 26 wt % of the ethylene polymer eluting between 40 and 76°C.; from about 52 to about 82 wt % of the ethylene polymer eluting abovea temperature of 86° C.; and a remainder of the ethylene polymer elutingbetween 76 and 86° C.
 17. The ethylene polymer of claim 16, wherein: thepeak ATREF temperature is in a range from about 90 to about 96° C.; fromabout 1 to about 5 wt % of the ethylene polymer is eluted below atemperature of 40° C.; from about 13 to about 24 wt % of the ethylenepolymer is eluted between 40 and 76° C.; from about 58 to about 75 wt %of the ethylene polymer is eluted above a temperature of 86° C.; and theremainder of the ethylene polymer is eluted between 76 and 86° C.
 18. Afilm comprising the ethylene polymer of claim
 17. 19. The ethylenepolymer of claim 14, wherein the ethylene polymer contains less than 0.1ppm, independently, of chromium and titanium.
 20. A film comprising theethylene polymer of claim 14, wherein the film has: a MD Elmendorf tearstrength in a range from about 40 to about 250 g/mil; a ratio of MDElmendorf tear strength to TD Elmendorf tear strength (MD:TD) in a rangefrom about 0.15:1 to about 0.55:1; and a haze in a range from about 3 toabout 10%.
 21. The film of claim 20, wherein the film has an averagethickness in a range from about 0.5 to about 8 mils.
 22. The ethylenepolymer of claim 13, wherein: the melt index is in a range from about0.1 to about 10 g/10 min; the density is in a range from about 0.91 toabout 0.94 g/cm³; the CY-a parameter at 190° C. is in a range from about0.3 to about 0.55; the average number of LCBs per 1,000,000 total carbonatoms of the ethylene polymer in a molecular weight range of 500,000 to2,000,000 g/mol is less than or equal to about 3; and the maximum ratioof η_(E)/3η at and extensional rate of 0.03 sec⁻¹ is in a range fromabout 4 to about
 12. 23. The ethylene polymer of claim 13, wherein: theethylene polymer has a ratio of Mw/Mn in a range from about 3.5 to about8; and the ethylene polymer contains from about 1 to about 10 LCBs per1,000,000 total carbon atoms.
 24. The ethylene polymer of claim 23,wherein: the ethylene polymer has a Mw in a range from about 70,000 toabout 185,000 g/mol; the ethylene polymer has a maximum ratio ofη_(E)/3η at an extensional rate of 0.1 sec⁻¹ in a range from about 2 toabout 10; and the ethylene polymer contains less than 0.1 ppm,independently, of chromium and titanium.
 25. An article of manufacturecomprising the ethylene polymer of claim
 23. 26. The ethylene polymer ofclaim 13, wherein: the melt index is in a range from about 0.4 to about4 g/10 min; the density is in a range from about 0.92 to about 0.94g/cm³; the CY-a parameter at 190° C. is in a range from about 0.3 toabout 0.55; the average number of LCBs per 1,000,000 total carbon atomsof the ethylene polymer in a molecular weight range of 500,000 to2,000,000 g/mol is less than or equal to about 2; and the maximum ratioof η_(E)/3η at an extensional rate of 0.03 sec⁻¹ is in a range fromabout 5 to about
 9. 27. The ethylene polymer of claim 26, wherein: theethylene polymer has a ratio of Mw/Mn in a range from about 3.5 to about6; the ethylene polymer has a relaxation time in a range from about0.002 to about 0.025 sec; the ethylene polymer has a maximum ratio ofη_(E)/3η at an extensional rate of 0.1 sec⁻¹ in a range from about 3 toabout 7; and the ethylene polymer contains from about 1 to about 8 LCBsper 1,000,000 total carbon atoms.
 28. An olefin polymerization process,the process comprising contacting a catalyst composition with ethyleneand an olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an ethylene polymer, wherein: thecatalyst composition comprises: catalyst component I comprising a singleatom bridged metallocene compound with an indenyl group and acyclopentadienyl group; catalyst component II comprising an unbridgedhafnium metallocene with two cyclopentadienyl groups; an activator; andoptionally, a co-catalyst; and the ethylene polymer is characterized by:a melt index in a range from 0 to about 15 g/10 min; a density in arange from about 0.91 to about 0.945 g/cm³; a CY-a parameter at 190° C.in a range from about 0.2 to about 0.6; an average number of long chainbranches (LCBs) per 1,000,000 total carbon atoms of the ethylene polymerin a molecular weight range of 500,000 to 2,000,000 g/mol of less thanor equal to about 5; and a maximum ratio of extensional viscosity tothree times shear viscosity, η_(E)/3η, at an extensional rate of 0.03sec⁻¹ in a range from about 3 to about
 15. 29. The process of claim 28,wherein the activator comprises an activator-support, an aluminoxanecompound, an organoboron or organoborate compound, an ionizing ioniccompound, or any combination thereof.
 30. The process of claim 28,wherein the activator comprises a fluorided solid oxide and/or asulfated solid oxide.
 31. The process of claim 30, wherein the catalystcomposition comprises an organoaluminum co-catalyst.
 32. The process ofclaim 28, wherein the olefin comonomer comprises a C₃-C₁₀ alpha-olefin.33. The process of claim 28, wherein: catalyst component I comprises ametallocene compound with a single carbon or silicon bridging atom, anunsubstituted cyclopentadienyl group, and an alkyl-substituted indenylgroup; and catalyst component II comprise an unbridged hafniummetallocene with two alkyl-substituted cyclopentadienyl groups.
 34. Theprocess of claim 33, wherein: the polymerization reactor systemcomprises a slurry reactor, a gas-phase reactor, a solution reactor, ora combination thereof; and the ethylene polymer comprises anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or anethylene/1-octene copolymer.